The Mammoth Book of Historical Crime Fiction

The Fourth Quadrant DOROTHY LUMLEY

Robert hefted the truncheon in his hand, feeling the warmth of the wood under his fingers. It was heavy, but then it needed to be to do this evening’s work. Inwardly he sighed. It was not work that he enjoyed, and it was not why he had joined the newly formed Metropolitan Police. But, judging from the expressions of some of the men around him, they were looking forward to this night’s work.

He cast his eyes over the police unit surrounding him. Some refused to meet his gaze. They were the nervous ones, often the youngest. Others, like him, had a set look that said: Come on, let’s get started, get it over with, then we can go home to our wives and sweethearts. But some met his gaze with a wink and a smirk. They and their sticks and cudgels would get pleasure from this night’s outing.

“All right Bob?” his friend Will, standing next to him, murmured.

“It still doesn’t seem right, breaking up a peaceable meeting, just because they’re talking about unions.”

“You’re in the Police now. Can’t take sides. Anyway, Sergeant says this ’un’s illegal.”

“Right boys, time to move forward.” Sergeant Cummings at last gave the order. Robert felt his pulse quicken. Gaslight flickered and hissed overhead — the lamplighters had already been abroad along Holborn and the Gray’s Inn Road on this damp October evening. The usual hubbub of carriages and carts and hansom cabs all fighting it out in the London street carried on. But he and the rest of his unit were about to enter a dark and unlit alley, right on the edge of a notorious Rookery. The notorious Rookery, in fact, where most of the poor Irish lived. Fortunately, the White Hart public house they were heading for, where the meeting was being held in a back room, or so they’d been informed, was nearby.

“You six go into the yard in the back, lay into anyone who sneaks out that way.” Sergeant Cummings picked the most eager-looking men. “Rest of you, follow me. Two short blasts on the whistle and we’re in. Right, boys?”

A flicker of white caught Robert’s eye as he moved into the alley behind Will. “Feargus O’Connor of the Northern Star and Robert Owen to speak concerning the Conditions and Plight of the Working Man …The Iniquity of the New Poor Law …” — he had to move on before he could read more of the poster. That would be a legitimate meeting, one they would not be called on to break up as had been happening so many times this past year all over the country. He hoped he might be sent on that detail, he’d like to hear the two great orators speak and, as he was expected to wear his police uniform at all times, he could hardly attend in his own right.

The two short blasts on the whistle reverberated down the dark alley. Already passers-by were jostling them and jeering and trying to knock their tall hats off. Any further into the Rookery and they would be in too much danger from the lawless folk who lived there, but here he could look back and see the safety of the well-lit London street — now, though, he was running forward, and found himself yelling, along with the others, as they charged into the meeting room at the back of the White Hart.

In the lamplight Robert had a glimpse of startled faces turned towards him, mouths open in shock and anger. Then the gathered men launched themselves forward. Robert staggered, but managed to keep his balance. It was every man for himself. He pushed and shoved, shouting all the while, “Outside, outside with you!”, while dodging fists and blocking painful kicks.

Above the noise he could hear Sergeant Cummings blowing his whistle and commanding, “This illegal gathering is over. Go home or we’ll have you in front of the magistrates in the morning.”

“We’re ’aving an educational meeting,” came one gibe.

“Yeah, you’re the ones breaking the law — the laws of justice and brotherhood!” came another.

The sergeant’s reply was lost in the general mêlée. Robert felt a blow on the back of his head, his reinforced hat saving him from the worst of it. He settled the hat more firmly on his head and looked round for the culprit. At the far end of the room he saw a tall bearded man standing on a makeshift podium made of boxes and planks. He wore a black suit and top hat, his stock was fresh and white at his neck, while two men in working attire stood at his side. He was continuing to declaim, one hand raised above his head, to the struggling mass below. “Stand up, stand up against our oppressors … are we not free men … the right to order our own destiny … we should have the right to vote, not just those with money and power … This is an outrage against justice and natural law …”

Sergeant Cummings had managed to force his way through to the front and was reaching for the ankles of the speaker. The two men beside the speaker sprang into action, hustling him from the makeshift stage and through a door at the back of the room. Cummings did not follow them. His orders were to break up the meeting, with force, and he’d go no further.

Robert began to lay about him again, more in self-defence than attack. He felt rather than heard his truncheon crack here on a shoulder, there on a man’s back. He didn’t put all his strength in it, just enough to send a message. He, Robert, was still in control, unlike some of the others on both sides around him, their faces red and contorted, spittle flying.

But, with the speaker gone, those who had been listening to him were losing their steam and there was a mass exodus for the door. Robert tried to stand back, but, unprepared, received an elbow in his stomach which took his breath away. He doubled over, coughing and retching. It was in that moment that he felt a hand shoved hard inside his tunic then as quickly withdrawn, but when he looked up all he could see were men’s backs and the heels of their boots.

“Will, Will,” Robert called out, catching sight of his friend. He instinctively pushed his own hand into his tunic. “I think I’ve been stabbed!”

Through both of their minds ran the memory of Calthorpe, the policeman killed only a year ago during a similar confrontation. Will hurried to his side; he had lost his hat in the affray, his hair was dishevelled and there was a smear of blood on his cheek. “All right, Rob, my friend, where’s he cut you?” he asked as he supported him.

“In my chest I think. He stuck his hand right in.” With trembling fingers he undid the remaining brass buttons that had not been wrenched off in the fight. “Funny thing is, it doesn’t hurt at all.”

As the last button came undone, a piece of crumpled and folded paper fell to the floor.

“What’s that?” Will asked, bending to pick it up and handing it to Robert.

Robert shook his head. “I don’t know.” He ran his hand over his shirt, then couldn’t help laughing. “I’m not hurt at all. Must’ve been pushing that bit of paper in. I’ve got the wind up me right and proper.”

“You and me both, mate.” Will squeezed his shoulder. “Reckon we deserve some ale after this. Maybe a visit to a chop house. Coming?”

“Good idea.” Robert automatically began unfolding the piece of paper. Why would someone have gone to the trouble of pushing this on him? The same person who elbowed him in the stomach so he couldn’t see their face?

“What the heck’s that?” Will asked, looking over his shoulder. “Looks like a lot of nonsense to me.”

They gazed at a jumble of letters, numbers and pictures. “This here’s Egyptian writing.” Robert pointed to hieroglyphs. “I’ve seen them in the British Museum. I can’t make any sense of it.”

“Did he have mad staring eyes, the man who shoved it on you?”

“Go on.” Robert poked his friend in the ribs. “No more than you do! All the same, I think I’ll pass this on to the Sergeant. It might mean something, though I don’t know what.”

“Another one of your hunches. All right, and then we’re off duty and can go for our supper.”

Robert nodded. Once he’d handed the paper over, it was no longer his responsibility and Sergeant Cummings could decide what to do with it.

Ada stared at her breakfast plate. Half a slice of toast was left. If she cut it in tiny squares and chewed each one as long and as slowly as she could, she would be able to complete the task she’d set herself at the same time as finishing her toast. Why was the 47 times-table such a tricky one? She continued reciting it in her mind. Although she tried to stop them, her lips kept trying to form the numbers, but chewing the toast helped hide that.

Across the table, her mother rustled The Times newspaper and gave a noise of disgust. Ada tried to shut out the sound, and speeded up her mental exercise. With her mother’s three friends all taking their breakfasts in bed, claiming they’d come down with autumnal colds, she’d seized advantage of her freedom from having to respond to their remarks about the weather, or the minutiae of the life lived by their Mortlake neighbours, to allow her mind to continue to play with numbers. She enjoyed not having their eyes constantly watching her, checking her behaviour and how much she ate. Her mother’s watchdogs — whom to herself she called the Three Furies.

Her mother gave another snort of rage, folded the newspaper and tossed it down. It was no good, she’d only reached 47 times 23, and her mother was about to launch into a tirade.

“Yet another one of these meetings by those uncouth ruffians usurping the name of Robert Owen for their own ends. When are the government going to put a stop to it? That’s what I want to know. The Police Force had to go in and break it up when they should have been out on the streets catching thieves and murderers. And it’s my taxes that pay for that. It will give the Co-operative movement a bad name, and set back all the good work of Owen, and Feargus O’Connor with his Northern Star newspaper.” She thumped the pink tablecloth for emphasis, making the silver spoons rattle in their delicate Crown Derby porcelain saucers. Ada sensed the footman wincing as he feared for the whole breakfast service.

“Their meeting place, some tavern or other, was set fire to; only the quick thinking of the Metropolitan Police managed to put it out. Irish malcontents or extreme radicals, that’s what they were. You’d think that the example set by what happened to those farm-workers in Dorset would have been enough to deter them, whether you think their fate was the right thing or not, but, oh no — ”

“Tolpuddle. They were from Tolpuddle, Dorset. Twenty men sentenced to transportation to Australia for seven years’ apiece. In March this year,” Ada said.

“Yes, yes, I know all that. Don’t interrupt me.” Her mother settled her lace cap more firmly on her dark hair, then fixed her fierce eyes on Ada. “The point I’m making, Ada dear, is that some unscrupulous men, pretending to be allied to O’Connor and Owen and Cobbett, with their talk of combining into unions, are instead using the common man for their own ends, not for his good. Their purpose is to destabilize the government and bring down the monarchy. They want to incite the mobs into a rabble running through the streets of London, burning and pillaging. Why, they’re nothing but … but Republicans!”

The word hung dangerously in the air. This was the spectre her mother hated and feared the most. Would England become infected by the Revolutions of 1830?

“I believe they only talk of rights and wages and conditions, Mama, not of — of that,” Ada said. “Especially as the Reform Act has not extended suffrage very much.”

“And what right do they have to question the natural order of things? The men who run the factories and mines bring prosperity, jobs and advance for everyone. They should be praised, not attacked.”

Ada pushed her plate away, abandoning the last two small squares of toast. She would not complete her task now. “They create wealth through their knowledge and daring, and invention. They carry the risk with their own money. Without them there would be no jobs, and starving families. A logical equation, it seems.” This was what her tutors taught her, even though the words sometimes had a hollow ring. Her mother espoused the Co-operative Movement, yet still feared what she called the “ungoverned elements”.

“And another thing.” As usual her mother didn’t listen to her, and her tirade was not yet over. “Here we are, spending money building workhouses for the poor to give them shelter and food — again out of my taxes — and yet they’ve done nothing but complain about them for the past two years.”

Ada looked around their comfortable breakfast room. The walls were a delicate shade of eau de nil and white, with mouldings of fruit and flowers. A coal fire burned in the grate, and they sat at a walnut table. Everything in this room spoke of good taste and good quality — and money. Money her mother had inherited. Servants stood, unmoving, by the wall, ready to fulfil any order their mistress might have.

Ada had seen, by contrast, illustrations of workhouses, with their bare stone walls and high windows, and had read how men and women were separated and that families were not allowed to live together. But she must not think about those things. For that way madness lay, and her mother did everything she could, for her daughter’s own good, to keep her from the possibility of that downward spiral …

“Lady Byron, a message for Miss Ada.” The footman, John, had entered carrying a silver tray on which lay a small white envelope.

Ada knotted her fingers together under the table and squeezed them, starting to count backwards from one hundred, to stop herself from feeling faint. She was not angry that her mother now read all her invitations first — “It really is for your own good.” She felt herself flush at the memory of last year’s folly. She felt again William’s caresses, his kisses — the adventurous thrill as they planned their elopement. Quickly, having counted back to one, she focused on The Times’s headlines, reading upside-down: “October 1834”, she read, then made out the words “King William and the Royal Party … Wellington …”

“It’s from our friend Charles Babbage.” Her mother’s pursed lips had broken into a smile. “He requests your company today to stimulate his mind in the discussion of logarithms and calculus.”

Ada held her breath and squeezed her fingers even tighter.

“I suppose I can let you go today. It is Saturday, and you are far enough ahead in your studies, your tutors tell me. But tonight is Lady Conway’s Ball, a fancy dress masque, so be sure you’re back in plenty of time to prepare for it.”

Ada managed to hold in her shriek of pleasure, but couldn’t stop herself clapping her hands. “Shall I wear my new red dress, Mama?”

“It goes well with your dark hair, and you might be seen while in the carriage, so, yes.”

What have I done to deserve such a day, Ada wondered as she left the breakfast room, giving a skip as she crossed the threshold. She was wanted, she was needed, and by the one man in whose company she could release all her passion for mathematics and know she would be understood. They could share their love for the arithmetical world. Furthermore, she would wear her new dress, and tonight there was her favourite — a fancy dress ball.

As she passed through the drawing room, her eyes slid over the painting above the fireplace which was covered by a green curtain. It was a portrait of her father, but she had never defied her mother’s wishes and looked at it. She did not want to gaze into the face of that wicked darkness …

“Welcome, welcome, my dear Ada.” Charles Babbage held out his hands in greeting and she felt their warmth coursing through her. His black wavy hair framed an attractive face with a fresh complexion. He was of medium build, with strong shoulders. “Is that a new dress? Most becoming.”

Ada smoothed down the folds of red silk decorated with yellow flowers. The sleeves were fashionably widely puffed at the shoulder and the skirt flared from the high waist, finishing just above her ankles. It had not creased in the journey from Mortlake to Marylebone.

“Let me ring for refreshments — hot chocolate? — and then I’ll show you the equations I’ve been working on, which only my mathematical muse will be able to fully appreciate.”

Ada took a chair beside the glowing mahogany table which was strewn with Charles’s papers. One wall of the room was lined with books covering all the sciences. There was a miniature cosmology on a side table, given to him by his friend the astronomer Herschal, showing the position of the planets around the sun. Around the room were various inventions both abandoned and in progress, such as the shoes for walking on water, and instruments for examining eyes. But towering above them all was the Difference Engine, awaiting its move into the new building next door, created especially for it and paid for by public funds. Solid and foursquare, with its brass columns and cogs, its ivory numbers and black plates, it seemed to Ada to be a machine in waiting, longing to have its mechanisms clicking and slotting into place and providing answers at astonishing speed to those mathematical sums it took the human brain so long to work out. If only Charles could persuade the government to release more money for its development.

As soon as she’d heard about it — the machine that was the talk of London society — she’d longed to see it, but her mother had at first refused. Then, finally, when she’d gone to see it on one of Charles’s Open Days, she had understood it instantly, and she and Charles had recognized each others’ passion for the world of numbers. And now she had another dream. She was eighteen, soon to be nineteen, but when she was twenty-one — surely, then, he would hire her as his official assistant.

As they bent their heads over pages of diagrams and figures, forgotten chocolate congealing in its cup, Ada sensed that this was as much an escape for Charles as it was for her. He grieved still for the loss of three of his sons — following that of his wife — and very recently her namesake, his daughter Georgiana. But in the pure precision, the light and air of mathematics, they were given respite from worldly emotions. Charles Babbage, inventor, mathematician, astronomer, and — yes, surely — his able assistant, Ada.

The knock on the door made them both jump.

“Mr Clark, Under Secretary to the Home Secretary, wishes to see you.” Barely had Charles’s manservant spoken, than a tall thin man was pushing his way past him, followed by a young stocky man in the dark blue uniform of the Metropolitan Police. When he saw Ada, the young man removed his tall hat and placed it under his arm, and then took up a position standing at ease beside the door.

“I apologize for intruding Mr Babbage,” Clark said. There was a gleam of excitement in his pale blue eyes and this, with an agitation in his manner, gave a sense of urgency. “We met at dinner at the Prime Minister’s house.”

“I do recall it, yes. Some Madeira wine perhaps?” Charles nodded to his manservant, who withdrew. “Sit down, sit down.” Charles waved a hand towards a chair, but Clark continued striding about the room, casting glances at the Difference Engine.

“I need to consult with you over a Government matter,” Clark said. “Can it be now?” He looked at Ada.

“May I introduce Miss Ada Byron, my assistant in all things?”

“Miss Byron!” Clark took her hand and bowed his head. “I am sure I can speak freely in front of you,” he said, then rushed on. “I remember well how you talked about ciphers and codes, Mr Babbage, and how you are amassing notes to write a book on them.”

Charles exchanged glances with Ada, his face lighting up. “Indeed. I have a short paper in preparation already, and I exercise my mind regularly by attempting to decipher the codes used in The Times personal column. Some messages are easily solved, but others prove wonderfully challenging.”

“I knew you were the right man to see this, and to tell us — is it some kind of code, or is it gibberish? And if it is indeed a code or cipher, can you break it to reveal its secrets? I thought perhaps the Engine could help us.”

Ada held her breath. Charles could be very touchy on the matter of the Difference Engine. But he laughed. “The purpose of my machine is to help us with speed and accuracy in reaching mathematical answers. It cannot make those leaps of judgement that the human mind can. And at the moment, it cannot even make those mathematical sums. I am thinking of a new Analyser but without the money that — ”

“What codes are you talking about, Mr Clark?” Ada interrupted him, to distract Charles from the subject of research funding.

“Ah yes. Constable Duckett, step forward and give your account of last night’s events at the White Hart tavern near Holborn, and give Mr Babbage the piece of paper.”

Ada noticed that the young policeman was not intimidated by his surroundings. He was clean-shaven, and he’d made an attempt to slick down his springy brown hair. His eyes were a darker blue than Clark’s.

“That was the Union meeting where there was a fire,” Ada said. “Mama was reading about it in the paper this morning.”

“A lamp was dropped, but the flames were quickly put out, Miss,” the constable told her, then continued. “But just before then, towards the end of the fracas, when the men attending the meeting was dispersing, I received a blow to the stomach and then this here paper was pushed inside my tunic. At first I thought I was stabbed, but then I found this piece of paper. Because I was bent over I did not see who put it there. I decided to give it to the Sergeant in case it was important.”

“Bravo,” Charles said, and took the piece of paper. “Did you see anything of the man who gave this to you?”

Constable Duckett hesitated. “Not really, I was bent double. He may’ve had a missing finger. Something like that.”

Constable Duckett then returned to his place by the door, as the Madeira wine arrived. As Ada sipped hers, the young constable met her glance equably, then looked away awkwardly. He’d not been offered refreshments; was that because he was only a constable?

“Look here, Ada, what do you make of this?” Charles said. He spread the paper on his work table and together they bent over it. Immediately she saw a pattern. There were four quadrants, each with its own distinct features. The upper left was composed of hieroglyphs, the upper right and lower left were what seemed to her random groups of letters. The lower right was some sort of equation with complex polyhedrons on one side, symbols and a rhyme on the other. Underneath were two shapes.

“It’s four — ”

“Yes indeed, those hieroglyphs will be quickly read. I have a book — ”

“The letters will need application of the code-breaking — ’

“Indeed, we can begin with the simple frequency system and go on from there — ”

“But those equations — ”

“Yes, Ada, they will prove troublesome, but I’m sure we can do it.”

Clark had stopped his nervous prowling and had been excitedly listening to their interplay. “Then you think it does mean something?” he interrupted.

“We won’t know till we’ve cracked some of it, but, yes, I think this is a coded message.”

As the two men talked, Ada stared down at the paper, allowing the pictures, letters and symbols to flow, reform, break up, so that her mind could explore and absorb without direction. On another level, she was aware that Constable Duckett was saying, “I don’t know why I was chosen, or whether I was mistook for someone else.” And Clark replying, “It feels as if we are being played with.” Charles countered with, “We have no certainties until we uncover the true meaning of the codes or ciphers.”

“Wanstead Abbey,” Ada heard herself saying.

All three men stopped speaking and stared at her. She pointed to the three lone symbols at the bottom. “Surely that’s a gryphon, and, beside it, what could be a lake, and the sign of a cross.”

“It could be any ecclesiastical building,” Charles said gently. “And those three symbols may be related to the context of the other codes — ”

But Clark had seized on her words. “Wanstead Abbey? But that’s where — ”

“I know, my … Lord Byron lived there.” She sounded as indifferent as she could. “It’s all I know about him.” She turned away and drank some more of the rich wine. It was William who’d described to her — in the most romantic terms — the now ruined Abbey where her father had once lived, and near which he was buried.

“It all falls into place!” Clark was saying. “This must be the focus for Republicanism, the hidden face behind the philosophical unionists and their talk of Charters and Rights. Is it Irish Home Rule, or some more sinister form of Radicalism? We must find out. I was right to take this seriously. It is either a warning to us, or we’ve intercepted a message destined for another conspirator. Mr Babbage, will you bend all your powers to unravelling these codes, and put everything else aside? We must know what it says. For the safety of the realm.”

On the carriage ride back home to Fordhook, Ada studied the copy she’d made of the coded message, with the Under Secretary’s permission. She knew Charles was right. They should not necessarily interpret those three symbols as meaning Wanstead Abbey. There had been no rumours, no whispers, of a movement using that name as their rallying cry. And the composer of the message could not have known that she, or anyone of her family, would see it. Until the answer was found, they must be open-minded. At home she had her own pamphlets and notes on hieroglyphs — it would be a race between her and Charles how quickly these could be translated. But she did not have the key to the rest. She hoped to learn from Charles.

Was Under Secretary Clark over-reacting when he feared a threatening conspiracy to overthrow the government and establish a republic? She sighed. Her mother was not the only one to worry about such things. Would a republic be such a bad thing, she brooded? No Englishman could feel proud of their recent monarchs, though William IV was not as embarrassing in his excesses as George IV. Lady Byron often remarked that the Court set a terrible example and did not command respect. But then she said the same thing about Members of Parliament too. Only the Duke of Wellington, now their Prime Minister, escaped her criticism, but those who hated the way he’d let the Reform Act go through were not republicans!

I must listen carefully at Lady Conway’s Ball tonight, she thought, and pay attention to what is being said about politics and the matters of the day, instead of just enjoying myself showing off my costume and dancing. At least I have the advantage in that my mind is trained to notice such things.

She put the paper away in her purse — made of matching red silk and decorated with a black transfer-printed motif of the Tower of London — and found herself thinking of Constable Robert Duckett. There had been an honesty about him, and his manner was neither subservient nor insolent. Why did he make her think of William? She managed to hide it from her mother and the Furies, but she still felt pain at the thought of the young man who would have been her husband for the past eighteen months, if their elopement had not been thwarted. They’d barely managed to make it down the driveway that night. Where was he now? She hoped he’d managed to obtain another post as tutor, and was comfortable somewhere. But, a tiny part of her acknowledged, it had been a lucky escape. His energy and ardour had not matched her own.

Not that she thought of Robert in the same way. He was only a constable, albeit good-looking and someone with initiative. A girl would be happy to be seen on his arm.

Robert pulled his coat closer around him against a squally burst of rain. What a dreary night to be out without my snug uniform, he thought. It was strange to be out without it. When he’d first joined the Metropolitan Police, freshly recruited from Bristol, he’d felt very conspicuous wearing it at all times, as he was pledged to do. Now he felt vulnerable without it.

He paused. Looking up and to his right he could make out, through the foggy gloom, the dome of St Paul’s in the distance. He was headed, though, for somewhere godless — or so people said — towards St Giles and the Rookery. One of those warrens of alleys and courts, with ancient houses that jutted out above till they almost touched, tottering and in danger of collapse. Not a week went by, it seemed, than one old house or another collapsed in a cloud of choking dust, killing anyone unfortunate enough to be asleep inside. The Old Mint, Turnmill Street, Saffron Hall, whatever the warren was called it was always the same, as densely packed with humanity as a sewer with rats. Sometimes two families occupied just one room, sleeping space on stairways was hotly contested, and spots in hallways rented out.

These people might scratch some kind of living in an honest job, but the vast majority were engaged in some form of criminal activity or another — from as young as an orphan boy who could pick pockets, to the ancient ones, bent-backed and grey. Whole courts were devoted to such trades as pick-pocketry, swindling, or confidence-trickstering. And nowhere could you escape the smell of unwashed bodies and clothes, of open drains and sewers and the dankness of regular flooding in the cellars from the River Thames, kindly returning the sewage that had been dumped in her earlier. He took an experimental sniff now, and nearly choked, his stomach churning.

What a contrast he thought, turning up his collar, from his visit to Mr Babbage’s house in Marylebone. The new houses in the West End were built of smart stone, the streets were wide and well paved and lit with the new gas-lighting at regular intervals. Not only there but all over London was the feel of a town making goods, selling goods, importing and exporting them, inventing them and advertising them. As well as sewers, there was a smell of money. The chasm between those with money and the huge number who lived in worse conditions than a pig in its sty seemed to grow bigger every day, especially as the numbers of poor were swelled continuously by those arriving from a failing countryside, their rural lives even harder than those in the towns.

Robert was one of the lucky ones though, even if his job might be dangerous at times, like tonight. “Duckett,” Sergeant Cummings had said five days after the meeting at Babbage’s house, his little sandy moustache bristling, “That government man has sent for you again. A special job he says. Mind you do your best.”

“I will Sarge,” Robert had promised.

He’d arrived at an address not far from the new General Post Office building near the church of St Martin-in-the-Fields. From not far off came the sounds of hammering and construction, as the fire-blackened ruin of the old Houses of Parliament was removed, to make way for the new grand building designed by Barry.

He was shown into a small, cold windowless antechamber painted cream, one wall being devoted to leatherbound volumes of law. Under Secretary Clark joined him in there, and began his usual agitated walking as he spoke in a breathless way.

“I could’ve called upon one of the old Runners — most’ve them have gone into private investigations, and it really is no good that we have no detecting force now, though I intend to put forward ideas to change that — but I decided the fewer who know the better. You’ve not been talking?”

“No, only me and the Sergeant know and we don’t even talk to each other.”

“Good man, good man. I have news. Mr Babbage has made some progress, in fact he sounded almost disappointed that the first quadrant of code was so easy to crack.”

Robert was still. “What does it say?”

Clark stopped in front of him. “It’s not good. It says: ‘You have looked on my works, and ignored them, the cleansing fire, the falling rocks. Beware my next eruption.’”

“You were right sir, it looks like a warning. What of Miss Byron’s reading of the signature?”

“It still seems possible, but we can only wait as they work on the rest. Babbage mentioned something about frequencies and transpositions which I don’t understand. I leave all that to him. Meanwhile, I have used my own official channels and have found that the mastermind of last Friday’s meeting lives and works in the Rookery, very near the White Hart Inn itself. I’m asking you to go there — not in uniform of course — and strike up a conversation, see what you can find out.”

“You don’t think our coder is the same person who organized the meeting then?”

“That’s Connor O’Brien, a hothead, with links to protection rackets, but this is not his style.”

Robert nodded. “The man who penned this message, though, he must be an educated man, maybe someone who’s fallen on hard times.”

“Or deliberately turned his talents to criminal activity. There are plenty of clever minds in these rookeries, the ones that organize the faking and the swindling.”

“But why choose such a random way of passing on his message?”

Clark’s face darkened as he paced up and down. “He thinks he’s a clever man, much cleverer than us. This is part of his cat-and-mouse game. If we don’t respond, he scores, then he tries again. Thank you, Constable Duckett, report back direct to me.” Then as Robert did not leave he said, “You have a question?”

“He says his previous messages have been ignored. What did he mean?”

“I was afraid you’d ask that. This is to go no further, understand?” Clark leaned closer and spoke in a low voice. “There have been two earlier messages, both dismissed as nonsense. One was pushed through Wellington’s letterbox and was written in children’s doggerel verse. It spoke of houses tumbling down — and there was that terrible collapse in Borough when many died and were injured. The second, we worked out, was Biblical References, and, when we found the verses, fire and brimstone were mentioned — ”

“The Houses of Parliament burned down earlier this year.” Robert was ahead of him.

“Exactly. There has never been any suggestion the fire was anything but an accident but … we can’t take any chances.”

Now, Robert looked up at the sign of the Inn. Outside was a board advertising an Ordinary Fish Supper. He was the bait, he thought, being sent in in the hope that their fish would reveal something of himself. Even though he would revert to his full Bristolian accent, and mention Dorset enough he’d be associated with the Tolpuddle martyrs, he was sure the people here could sniff out a policeman a mile away, however much he tried to disguise himself.

Four tankards of watered down ale, with an “aftertaste of the Thames” later, he’d made four new “brothers”, who promised to let him know when the next political meeting was being held — “Legal or otherwise” — and they’d make them all illegal if they could. “Combined, we can make a difference, ain’t that right?” one had said.

He staggered across the threshold, the sound of Irish singing in his ears, and began to thread his way along the alley towards the bigger, safer street ahead. He tried to marshal the few facts he’d gleaned into some sort of order before they floated away in a beer haze. Names of speakers, the principles of combining into unions; was there any fact or name that stood out? Someone who was a bit different, whether in speech or beliefs? He thought there was something that had been said, but what was it? He tripped on something sludgy and nameless in the dark and automatically put out a hand to steady himself when …

Pain exploded across his left shoulder, he lost his balance completely and collapsed on the ground, hitting his forehead. All the breath seemed to have left his body and he struggled to breathe. As he blinked to clear the cloudiness from his eyes, he felt the hard cap of a boot connect with his ribs, then another. He tried to curl into a ball but could not make his body obey. The shock of the attack had robbed him of control over his limbs as well as his senses.

Then he heard a shout, “Here, you! Leave that man! Get off him!” He heard footsteps running off, and then felt the blissful end to the well-aimed kicks.

Robert managed to pry his eyes open. A face swam into view.

“What took you so long?” he managed to croak. “Nearly had him, though, didn’t I?”

“Sure,” came Will’s cheery voice. “You had him against the ropes. Think you can stand?”

With Will’s arm supporting him Robert managed to clamber upright on to wobbly legs.

“Ouch. He must’ve had steel caps on those boots. I thought you were never coming. You know I bruise easily!”

“Had to finish my ale didn’t I, keep up appearances. Besides, I’d bought the round.”

“Nothing … to do … with the pretty barmaid then?” Robert panted, then groaned as he took a step.

“What an idea! Good thing you asked me to shadow you and watch your back. What’ve you done to rile that man? Owe him some money do you? But isn’t this the place we came the other night.”

Robert nodded, and instantly felt sick. “Thought I’d try and spot the one who shoved that paper on me, find out why me … ooh, I feel dizzy.”

“Here, I think you need proper attention.” There were voices ahead on the high road and Robert heard Will saying, “This feller’s been attacked, robbed most like — stop a cab can you, he needs a doctor,” before he lost consciousness.

Ada walked swiftly along the corridor of Westminster Hospital behind the orderly. The hospital still smelled new and fresh, not yet overlaid with the stench of sickness and medicines. She felt a tingling sensation between her shoulder-blades, as if her mother was watching her, or at the very least knew exactly what she was doing, and was planning a severe punishment as well as a lecture. But she would be only ten minutes here, no more; and who could object to her spontaneous gesture of giving — bringing a basket of food to the sick and needy in this brand new building, just opened on Broad Sanctuary, Westminster, on her way home from a shopping trip in the Strand? The waiting driver in their carriage would not know she had actually spoken to one of those needy patients.

“Constable Robert Duckett, Miss,” the orderly said, opening the door to a private room and, leaving the door open, positioned himself on a chair outside.

Robert was sitting up in bed, several pillows behind him. His forehead had a bruised swelling on it and he was pale, but otherwise well — and surprised to see her.

“Why, whatever are you doing here — ”

Ada held up a finger before he could say her name. “And why shouldn’t your cousin visit? Were you hurt badly? What happened?”

He quickly understood. “Thank you, cousin, I was set upon from behind near the White Hart Public House. I hurt my head when I fell.” He touched his forehead then winced, “But it’s my ribs he gave a good workout, and they’re all bandaged up. Nothing broken though.”

“Do you have everything you need?” Ada asked. “I’ve spent so many long hours in the sick-room at home, struck down by debilitating conditions — erm, as you of course know — the hours can hang heavy. I could send you a book.”

“Thank you. And my friend Will’s sending in pies for me to eat.”

Ada glanced over her shoulder. The orderly was standing in the middle of the corridor gossiping with a passing laundrymaid. She dropped her voice. “Did you learn anything? We’ve been working night and day on the ciphers. I expect you heard we broke the second quadrant.”

“I learned nothing; but, the second quadrant …” Robert leaned forward, eyes bright.

“‘Where many are gathered together, and the light is bright, there shall I strike,’” she repeated the words carefully. “It was the simple frequency method that worked in the end; we found that every third — ” She broke off, as Robert leaned back, eyes closed, frowning. “Are you all right? Some water?” She reached clumsily for the glass at his bedside, accidentally brushing his bare arm, but he didn’t seem to notice, or was too polite to react.

“Very Biblical sounding,” Robert said. “There’s something there but, no, I can’t recall.” He opened his eyes, their blueness startling her as she leaned close. “That knock on the head has affected my memory. I was sure there was something said — a name, maybe a place, in the White Hart, but it’s gone now.” He looked at her. “I call him the Prankster, this code-maker. It’s all about proving how clever he is, making us run round in circles. He knows he’s hooked us, with me going in that pub.”

Ada gasped. “You mean it was him who attacked you? Not one of the Radicals or a robber from the Rookery?”

“Not him in person, I suspect, but word got back to him the police were sniffing around, and he sent us another message of a different kind. How did you know I was in here anyway?”

“When Mr Babbage was telling Mr Clark our progress with the code, Mr Clark said we were on the right track, and that he’d sent you to the public house ‘with no results but a cracked head’ was how he put it.”

“Huh!” Robert said.

Ada heard the orderly returning to his chair, and straightened up. “I have to go now. God speed your recovery. You are a brave man,” she added, cheeks flushing, before marching out.

Robert lay back on his pillows. Brave? He didn’t think so, but, if a young lady wanted to think it, he didn’t object. And now Miss Ada Byron would return to her world of dances and supper parties, and he to his lodgings — his family far away in Bristol.

He imagined himself at a supper party — and what a botch he would make of it — when he had a sudden thought: November the Fifth. That was a night when there would be crowds and bright lights, and a man with a political statement to make could set the largest number of tongues wagging. And perhaps even explosions of his own to make. He’d pass that on to the Sergeant for what it was worth.

But just for now he was feeling very uncomfortable and very tired. Time to have another sleep.

“Miss Byron! I did not send for you.” Charles Babbage fiddled irritably with the small microscope in front of him, not meeting her eyes.

So, he was in one of his moods, and she was Miss Byron today, not “my dear Ada”. The maid who’d announced her still hovered in the doorway, in case she had to show her out again. Ada stepped forward, taking off her bonnet and gloves and handing them to her. She would not be deterred by his grumpiness. The maid shrugged and left the room.

“I saw Constable Duckett two days ago,” she said sharply, noting that he wore his oldest smoking jacket, its elbows rubbed, and his stock was all askew. “In hospital.”

“What?” He sat up and looked at her, but not with his usual sociable warmth. “Oh yes, Clark said something to me, I don’t know what — ”

“That’s right,” Ada said, sitting on the low Ottoman that now stood where the Difference Engine had been. The Engine had at last been moved to the building next door. “Mr Clark sent him there to find out more information. The Constable was very brave …”

Charles muttered something under his breath that sounded like, “Spare me another one of your heroes,” but she ignored him. A black mood was not to be indulged. Lady Byron had taught her that lesson well.

“I have not heard from you in three days. We must redouble our efforts on the cipher. The Prankster knows we have it, or he would not have set upon the Constable. We must — ”

“It’s all folly. What can I do about it?” He stared gloomily at the blank wall above her head, where the Engine had stood.

She sat bolt upright. “You can do everything! Supposing Mr Clark is right and the code is warning of some terrible event to come. We can save lives, preserve the stability of this Government — ”

“Why should I care what happens to this Government? Short-sighted fools that they are.” Charles jumped up. “None of them has any understanding of what I can do, of what I can achieve. My ideas — the new ideas of any inventor — are like pearls before swine to them. I’ve told Wellington I must start again, build a newer and better Engine; maybe he understands, but those around him are dolts and dullards.”

He must have had his latest request for funding rejected, Ada thought, and that coupled with his long running dispute with the engineer who built the Engine and who now refused to return the plans, would explain the black cloud over him.

“You will prevail eventually, Mr Babbage,” she told him. “With me at your side, we can achieve everything.”

He stared at her. The flush left his cheeks. He was about to speak when there was a knock at the door.

“Miss Byron, good morning.” Charles’s mother-in-law stood in the doorway with Dugald and Henry, Charles’s youngest sons. They wore warm coats. “Charles, I’m taking the boys out for fresh air and exercise. Say goodbye to Papa, now.”

Ada watched as he spoke fondly to his sons, patted their shoulders, and then went to the window to watch and wave as they crossed the street. His eldest son was visiting relatives in Devon.

Now can we get back to the code, she thought. It was like an itch in her brain, the longing to fill her mind with puzzles and patterns, calculations and calculus. She’d lain awake for most of the night yet again, with figures and numbers whirling and cascading through her mind — as if she was the Difference Engine herself — and till her heart was hammering, and she’d broken out in a sweat. Only here could she find some relief from the pressure of — she did believe it sometimes — her genius.

Charles was ringing the bell to the kitchen. “I’ll order some coffee to be brought to the dining room and we can use the table there. I want to be away from this room with its aura of doomed projects.”

At last Ada could slide into that other world, the one of symbols and of certainties, of patterns that sounded in her mind like music. She passionately believed that if she followed the logical steps, the truth would be revealed. Nothing would be hidden from her any more. She’d find an absolute truth, without questions or evasions; no hidden meanings or obscurities. In this world her mind could soar, her heart and body be left behind. If only she could stay and lose herself in this world forever.

Coffee cups drained and pushed aside, they worked on the lower left quadrant. Having exhausted the possibilities of the frequency method, Charles suggested they now move on to transposition. “As you know, Ada, this is how science works. We work our way through each of the postulations till, at last, one of them matches all the parameters and we can fit the key. Although,” he added, with the twinkle returning to his eye, “A leap of the imagination often helps too.”

Ada gave an internal shudder. Imagination. That’s what her father had had, in abundance. It had led to terrible things. What exactly they were, she had not been told. Sometimes, when she languished in her room in one of her ill periods, all sorts of weird images came into her mind and made her feel worse. They were not to be spoken about, her mother had made plain. He was not to be spoken about, but she must never forget that he was a ruiner of lives — his own as well as others’.

The letters swam before her eyes and she did her best to focus, and to banish these thoughts before they dragged her down again. Apply the method, following Charles’s instructions, and she would be in control again.

After a while she became aware that Charles had put down his pen and was staring into the distance. She became as still and quiet as possible. This was what he was like when new ideas were coming to him. He got up and went to the window, staring up at the cloudy sky then down at the autumnal leaves that had collected on the pavement. He turned back.

“That’s it,” he said. “While we are still working on the cipher to uncover what message our man is sending, I will send him one of my own. You said that Constable Duckett was ordered to that public house in the hope of drawing out — what did you call him? — the Prankster. It may not work, but my guess is that this man will also enjoy the challenge of The Times Personals. I shall place a message for him.”

“What will you say?”

“That’s what concerns me. How about something like ‘The net is getting tighter. You cannot succeed. We are very close.’ Or something like that,” he waved a hand airily, seeing Ada’s frown.

“But how will he know it’s for him, that could be for anyone.”

“True, and that’s why, Ada, I have a special request.” He sat down again beside her and took her hands in his. “I would like to use the symbols that you interpreted as Wanstead Abbey, along with the name of Byron, perhaps a line from Childe Harold. Would you allow that? It’s all I can think of using — we could mention bright lights, being ignored — but again that’s open to interpretation.”

Ada lifted her chin. Robert had not been afraid, neither would she. And she knew none of her father’s poetry, so it would not matter to her. “You must use it. Why not ask him to meet you? Or ask what it is he wants!”

“I’ll work on it. Thank you, Ada.”

“But — don’t you think we should ask Mr Clark first?”

“Hah — if we wait for government departments to make up their minds, we’ll still be waiting for an answer at the next Millennium!”

“Is the syllabub to your liking, Ada?”

“May I fetch you some wine, Miss Byron?”

“You are looking a little pale, are you chilled? Shall I fetch your shawl?”

Ada smiled. It was certainly flattering to have the attention of these young men, to be surrounded, when other young women looked on in envy. And she never lacked for partners when the dancing started, which was good because she enjoyed it so much. Yes, it might be because of her name and her fame but, if they didn’t like her, surely they wouldn’t stay?

“Yes, and yes please, and no thank you, I’m not cold,” she answered. As one swain went to fetch her some wine she said to the other two, “Have you seen Mr Babbage’s Difference Engine? I’ve had the pleasure of working with him on — ”

“A most fantastical machine, I’ve heard,” interrupted the first young man hastily. “But I wanted to ask you, Ada, if there was perhaps something fantastical at the theatre you would like to see? Perhaps your Mama would allow — ”

“Nonsense, not the theatre. Miss Byron, I could arrange a day at the races, would that be more to your liking?”

“It would indeed. I was at Doncaster not long ago, and the thrill of it! I want to learn about horses, and, of course, the arithmetical calculations on the betting odds are intriguing — oh!”

Her wine was being handed to her, but not by one of her swains. Instead, it was Mr Clark.

“Good evening Miss Byron. May I compliment you on your yellow outfit? A most striking and vivid combination. A beacon in this room.” He indicated the rest of the soirée in the candle-lit room. Small baize-topped card tables at one side were fully occupied. In the far corner a small group sat listening to the gentle tones of a guitar played by an Italian maestro. Still others, like her own coterie, sat gossiping together on chaise longues and low padded chairs in the French style. The cold buffet supper was over, the last of the desserts now spooned up and the plates and bowls cleared away by the servants.

Ada felt her spirits lift further, having previously resigned herself to an evening of pointless small-talk.

“May I?” He sat down, and the two younger men melted away.

“Have there been any developments?” Ada asked, managing to lower her voice. “I have not heard from Mr Babbage for two days. And how is Constable Duckett?”

“Mr Babbage has broken the third quadrant. ‘I have many masks. I am the Destroyer.’ Strong words. They are the Prankster’s, not mine.”

She noted he was using Robert’s name for the code-maker now. “Did Mr Babbage say anything else?”

Clark shook his head. Candlelight reflecting from his spectacles made his eyes seem to glitter. “Only that the solution to the final quadrant would take longer. As you know, it contains geometrical figures and a nonsense rhyme. Mr Babbage says there are no equivalences for these, so the key could be anything. Does he threaten to destroy Wanstead Abbey? What reason would he have for doing that?”

“I think of nothing else,” Ada said. “Some nights I hardly sleep, my mind cannot let this puzzle go.”

“I’m sorry to hear that your rest is disturbed. Perhaps we should talk no further.”

Ada shook her head. “It would make no difference. I want to know — I dearly want to meet the challenge the Prankster has set us. And when I look around a gathering like this I wonder, is he here? Could he be in this room right now?”

Clark was observing her closely. “Especially as he tells us he has many masks. Does this mean that he can mix with any part of society he chooses? I am beginning to think that he is no radical, he is not trying to change a political system, he is simply after notoriety.”

“As Mr Babbage says, he has set a challenge. Do you truly think he set fire to the Houses of Parliament? And what about the ‘collapsing houses’ he mentions?”

“We have no way of knowing on the former. As for the latter, these old buildings in poorer areas from times gone by are not looked after, and do collapse from time to time anyway.”

“I have tried to think where he means to strike next. Could it be an assassination attempt on the King? There have been several already.”

“My choice is the railways. Perhaps a bridge. I am confident it will be in London. I have every policeman and special agent on full alert — including Constable Duckett, yes.” He smiled. “That young man is out of hospital and taking some days off to recover, unpaid of course. But now, I think I’d better leave you, before tongues start to wag.” He stood up and bent over her hand.

Ada was suddenly aware of her mother’s close scrutiny from the group around the musician. She sighed inwardly. Her mother would not rest till she had tracked down every last detail of Clark’s family and background to find out if he was grand enough for her daughter. Her mother was suspicious enough of her already. She’d caught Ada scrutinising the Personals, looking of course for Babbage’s message to the Prankster. Now her mother had forbidden her to read the paper. “I shall be most annoyed if I find you are conducting correspondence with a young man through that column,” she had said, despite Ada’s protestations that she was exercising her code-breaking skills, as suggested by Mr Babbage.

So now it was a race to solve the fourth quadrant. She would put everything aside and think of nothing else.

Robert put his head down and literally pushed his way through the throng that was shoving and jostling its way between the carriages and carts that had come to a standstill at Charing Cross. There was a “lock” on. The numbers of wheeled traffic had built and built till no one could move, though this was not one of the most notorious places for it to happen — they were towards the City.

Carters and drivers yelled and shook their fists, horses snorted and struggled in vain in their harnesses and shafts. Robert battled his way through this tumult to the south side of the Strand, where he breathed easier and began to walk eastwards.

It was a crisp bright autumn morning with a chill in the air. Sunlight slanted on the advertising in shop windows, and on tin plates fastened to the walls above. A myriad of manufactories, shops and cafes shouted their wares at him. If Charing Cross was the centre of London, then the Strand was its beating heart. It was the new London, brash, confident, a centre for all the forms of commerce, industry and entrepreneurship. Even the pavements were lined with women and children selling flowers and fruit, from baskets on the ground.

After a while he turned to his right into an alley and began the descent down to another world, to an older London that still lined the river. He was in deep shade now — cast by the brick walls and timbers of tall buildings. The noise, colour and life were left behind. He was entering a world of scuttling shadows, of figures that hid in doorways, of glimpses of pale faces behind grimy windows hunched over soulless tasks. He pulled up the collar of the patched coat he wore, and pulled down the lip of his shapeless greasy cap. Both had been bought for a few pennies at a rag-pickers, the boots on his feet with worn heels and holes in the toes from Seven Dials.

As far as Sergeant Cummings was concerned, Robert was resting in his lodgings — he had enough savings left after what he sent home to his mother in Bristol to tide him over. Not even his good friend Will knew what he was doing.

A whiff from the Thames carried on a rising breeze caught his throat, and he coughed till he retched; and that made him clasp his side which still ached from the kicking he’d received. He still had flashes of pain in his head, too. This was one of the reasons that had made him decide to investigate by himself. He wanted to make the man who’d ordered his beating pay.

The other reason was the bloodless face, blue about the lips, of the body of a young man that he’d witnessed in the morgue yesterday afternoon. Will had been off-duty, so had come to meet him at Westminster Hospital and share a licensed cab home with him. As they’d waited at the kerbside, Will had said casually, “Remember you told me, when that paper was shoved on you, you thought the man was missing a little finger? A lad with a missing finger showed up on the morgue reports, fished up at the side of the Thames. Thought you’d like to know, seeing as how you went back to the White Hart on account of that business, and ended up here for your pains.”

Robert gripped his arm. “Can we go to the morgue now? I’d like to see him.”

“What, reckon you’re well enough to be looking at dead bodies? Will they let us in?”

“I’ll tell them the Sarge sent us and square it with him later.”

Will sighed. “Well, you’re his blue-eyed boy at the moment. Can’t say it’s much of a substitute for a quiet pint of ale, but, all right then!”

They’d talked themselves into the morgue, but Will decided to wait in the office, while Robert was taken through to view the body. When the cloth was pulled back he’d stared down into the face of a young man he recognized. Not from the night they’d broken up the political meeting, but from the White Hart. He’d been one of the group of men he’d struck up conversation with. A quiet, nervous lad who’d laughed in the right places but not said much. And now that elusive memory that had been knocked from his head when he fell, returned.

A newcomer had sidled up to the lad, face obscured by his felt hat so that all that could be seen were the brown stumps of his teeth and a chin disfigured by a deep scar. A few words were muttered, the young man had gone pale. He’d quickly downed his drink then got up and left.

Robert recalled now the name he’d managed to catch, through the hubbub of the public house: “Chapterhouse Stairs.” He knew these stairs, or steps, down to the riverbank, were situated between Temple and Puddle Dock.

“Where was the body found?” he’d asked, and was not surprised to be told, “Near Puddle Dock Stairs.”

He’d not said anything to Will beyond “Yes, I think that’s the lad. Tell the Sergeant for me will you? I think I need to go and lie down now.” Will had understood and gone for a drink on his own, while Robert had devised his plan and gone out to buy his disguise. And now here he was the next morning trudging through the maze of lanes that went beyond the Temple, heading towards Blackfriars and Chapterhouse Stairs.

At last he stepped on to the narrow wharf constructed of large blocks of stone, from which a flight of steps led down to the muddy shore below. A few wooden boats, one with a mast, were pulled up on the mud, and a few brave souls were picking through the smelly ooze to see what treasures the murky waters might have washed up. Anything that could be sold for a farthing or more was worth keeping.

Robert eyed the several derelict buildings that lined this small wharf. Wide wooden eaves jutted out over upper storeys, which in turn jutted out over the lower ones. There wasn’t a straight line to be seen; all the timbers, windows and bricks seemed to be at odds with one another. As he wandered slowly by, he glanced inside. One building appeared to be some kind of offices, with clerks scribbling over piles of dusty papers. Another, a sort of chandlery. The third seemed to be unoccupied.

Robert slouched on past. He’d find himself a hidden corner out of the wind and get himself comfortable. He had a couple of pies he’d bought from a passing pieman, and a stone bottle of ginger beer, as well as an old blanket rolled up in his pack. There were worse ways to pass a sunny day than watch all the craft going by on the river, and the mudlarks at work below.

Ada felt the warmth of the late October sunshine on her back as she strolled her favourite walk between the market gardens that ran down to the Thames. It was a circular walk from Fordhook to the river and back. Winter vegetables grew in ordered rows, and a few late butterflies and bees foraged in the hedges. Behind her she could hear her tutors Dr King and Miss Noel deep in discussion on a philosophical point.

She quickened her pace. Ahead lay the grove of willows that she loved, and beyond that the small wooden jetty where she could stand and watch the flowing water, see the boats plying by, and find a moment’s peace. Particularly, she wanted to forget her mother’s pronouncement on Mr Clark. She’d researched his background and found it severely wanting on his mother’s side, two generations back. “Barely more than a seamstress,” her mother had announced. “You’d better not be planning a secret alliance.” She’d watched Ada even more closely, and she was still forbidden reading The Times.

In her purse she carried her notes on the fourth and last quadrant of the secret cipher. She’d hardly slept the past two nights for trying to puzzle it out, not caring if her mother thought she was pining romantically. But to no avail. “10S, 15C, what is the rest of me?” Ten times S and fifteen times C? That was the correct mathematical notation. Then last night she’d wondered if it was proportions. Ten plus fifteen was twenty-five, so 75 of what, to make one hundred? It made no sense to her. As for those polyhedrons, she’d found herself idly redrawing them, separating out each individual shape, and turning them into a necklace. Could some of them represent jewels? Then, annoyed at her inability to penetrate the Prankster’s cipher, she’d put a big cross through it all.

Quickening her pace again, she glanced round. Good. They’d stopped, deep in argument. She lifted the willow fronds and hurried through the grove to the jetty. There she intended on tearing up the paper into a hundred tiny pieces and flinging it into the river. From henceforth she was going to renounce all codes and ciphers!

A small skiff was moored to the end of the jetty with one man sitting at the oars and another standing beside it on the jetty. She turned her back on them and was reaching for her purse when she felt a strong arm about her waist. “If you want to see your friend Babbage alive, you’ll come with me and quiet about it.”

In shock, heart thundering, she gasped for breath as the man on the jetty hurried her into the waiting skiff, and the oarsman — a big bearded fellow — pulled fast into the river, heading for a larger boat. The man who’d taken hold of her now draped a hooded cloak over her. “Keep silent,” he hissed. “Or Babbage don’t live to see another day.”

Ada heard herself whimper. She closed her eyes in terror. Could it be true? Was Charles’s life under threat? What had been done to him? The boat rocked wildly and she felt nauseous, putting a hand to her mouth, as she was quickly bundled on to the large boat.

“Lie down!” came the order, and she felt a foot placed on her back as she obeyed. Now she thought she could hear a faint cry of distress, like a marsh bird, from Miss Noel at finding her gone.

As the boat wallowed in the water and her stomach heaved, she kept her mind fixed on one thing. Charles is in danger. For some reason I am part of this — perhaps I can help him.

Robert jerked his eyes open. Dammit, he’d fallen asleep. What had awoken him, apart from the uncomfortable stone that was pressing into his back? Voices, he thought he’d heard voices. Stiffly, he forced himself to sit upright so that he could see over the weather-beaten boards behind which he’d found his pitch. A new boat was being pulled up on the mud, by a large man with a lot of woolly grey hair and a beard. Two other figures stood inside: a man and a woman in a rough woollen cloak.

Robert looked around. All the mudlarks had scattered and were determinedly looking the other way. They knew who these people were, Robert thought, and apparently they were people it was best one didn’t know anything about.

The man on the boat said something, but he couldn’t make out what, and then the bigger man lifted down the woman and they all went up the stairs and headed for the building he’d thought was unoccupied. The big man was glancing around, as if to make sure no one was watching them. Robert kept very still.

Then, as clearly as St Paul’s bell, he heard the woman say “Is he in here? Will I see him now?” For answer, she was escorted in, and the door closed behind them.

He frowned. It couldn’t be. He must be imagining it. Were his brains still scrambled? But that voice — it sounded like Miss Byron. What could she be doing here? He began to struggle to his feet. He had to find a way to get inside — or at least see inside — that dilapidated building.

“Are you telling me the truth, Mr Babbage? She has not come here to your house? And you know nothing of any romantic liaison?”

“Believe me, Lady Byron, I’m as worried as you are. She has not come here, and I’ve not seen her since she was last here several days ago. As for romance — we confine our discussions strictly to science and mathematics, and matters of the higher mind.”

Lady Byron bit at her knuckle as she wandered to and fro in Babbage’s drawing-room. “Then where can she be?”

“How long since she disappeared?”

“Four full hours. She’s never been a robust child, and without proper care she might easily fall ill. Where has she gone? I hope the foolish girl did not have romantic notions. I’ve seen her reading The Times Personal columns, but she assured me — ”

“Ah, that would be because of me. We were — testing out a new code.”

“So she was telling the truth.” Lady Byron sank into a chair and put her head in her hands. “She can’t have … it’s too much to think … it can’t be in her blood … the water — ”

“I’m sure she has not taken her own life,” Charles declared bluntly. “She was too engaged in our mathematical studies. There is only one answer. She must have departed by boat. Yet no one saw her?”

“Her tutors did not see her on any of the boats passing by. Only her purse was lying on the ground.”

“Do you have it with you?” It was clear now to Charles that Ada has been abducted and hidden on one of the passing boats. If she’d gone by choice, she would not have dropped her purse. Had she left it on purpose? Might there be some clue about it?

Lady Byron opened her own bag and handed the purse to him. “I showed it to the police, but they did not need to keep it.”

Charles also sat down, and opened the clasp of the yellow satin bag then emptied the contents on the mahogany occasional table in front of him. He stirred them with his forefinger. A handkerchief with the initials AB entwined in red embroidery in the corner. A tortoiseshell comb. A small mirror. For some reason he thought of his beloved daughter Georgiana, so much missed, and his eyes misted over. Ada could not be a substitute for her, but he felt the same fatherly protective instincts for her as he had for his daughter.

He blinked. There was also some paper. He opened it up and recognized the elements from the fourth quadrant, whose solution had so far eluded him. Her busy mind had been working hard on them. He scanned her notes and suggestions, and the back of his neck suddenly prickled with excitement. She’d written “Proportions?” and what was this, a decorative necklace?

Of course! His mind leapt ahead and reached the conclusions she had not. But then he’d been blinkered by following the normal code-breaking routes, whereas she had made a sideways leap of the imagination.

“Lady Byron, may I take this? I have a contact who may be able to help us.”

“Anything — but hurry. Her reputation! Poor girl.” She gave a sob.

“Please wait here. I’ll send a messenger as soon as I can.”

Hatless and shrugging into his coat as he ran downstairs and out into the street to hail a hansom cab, his mind worked feverishly. Even though Ada had crossed through her workings and written “hopeless”, he was sure she’d made the right connection. The other 75 was saltpetre — combined with 10 parts of sulphur and 15 of carbon, it formed gunpowder. If so, then could the jewels on the other side of the equation be a ransom? Pay me a King’s ransom in jewels, or Wanstead Abbey would suffer the same fate as Parliament! Was that what the Prankster was threatening? No, why bother to blow up Wanstead Abbey? It had to be some other ecclesiastical building — and where else to make a bigger mark than St Paul’s Cathedral!

Robert crouched on the outhouse roof to regain his breath before testing the stability of the drainpipe above him. He’d first tried knocking at the door of the building, and, when the big fellow with wild woolly hair had opened it, he’d said, “Any knives need sharpening? Any rags you want got rid of?”

“Piss off or you’ll be buried so deep, even the mudlarks won’t find yer.” And the door was slammed in his face.

As he cast about the row of ancient buildings looking for another way in, by luck he saw a messenger-boy emerge from the door where he’d seen the clerks scribbling away. He gave him the Under Secretary’s address, his own name and that of the Stairs, plus a silver coin. He could only hope he was an honest boy.

A short while later he’d come across the entrance to a very narrow gunnel that ran behind the buildings, and now he was attempting to reach a first floor window to force his way in. He shivered. It was cold and dank here and he felt sick and sore. But he had to find out if Ada was inside, and why. Bracing himself, he took hold of the drainpipe.

It was getting dark, Ada noticed. The room she’d been forced into was getting gloomier by the minute. She’d been standing upright in the middle of the room for most of the time since being locked in. The floor was bare boards and there was no furniture, only a pile of musty sacks in one corner.

Her first action had been to look out of the one small window but all she could see was a brick wall opposite and a tiny glimpse of sky above. And then she heard them. Rats — mice — scuttling in the walls and above her head. There would be silence and then they’d be running by again. She visualized thousands swirling through the building. She tried not to think of the Plague, of rat bites — she stared down at her hands and saw to her disgust how they trembled.

She longed to sit down but could not bring herself to use the sacks. Supposing they were infested with fleas? Once or twice she sat down on the hard floorboards in the centre of the room, the only place she felt safe. She could imagine hundreds of beady eyes peering at her through cracks … horrible!

She’d tried banging on the door and shouting, but it had had no effect. She had then pressed her ear to it and heard the two men who’d brought her here laughing and cursing. It sounded as if they were playing cards. They ignored her.

She was cold, hungry and afraid, but as time passed her strongest emotion was anger — at herself. How could she, clever Ada, have been fooled so easily? Charles Babbage wasn’t here. She’d been tricked. But why? They knew of her association with Charles. Did that mean she’d been watched? And what did they want of her?

She heard the door being unlocked and drew herself up straight, assuming one of her mother’s sternest expressions. She would meet her fate with dignity.

In the glow of a lamp, a new man stood framed in the doorway. He gave a slight bow of the head. “Miss Byron, come and join us.”

Hesitantly she followed him into the outer room, which she’d only glimpsed before. A fire burned in the grate with hall chairs either side, while her two abductors sat at a small card table on the other side of the room. They glanced at her then resumed their game.

“Sit,” said the newcomer, indicating the chairs by the fire. She managed to make herself walk over and sit down. She watched as he poured some wine from a beautifully engraved decanter into equally exquisite glasses, and handed her one. There were other items of quality in the room too, she noticed. A French clock on the mantelpiece, and the rug at her feet was Chinese silk.

The man sat opposite her. His trousers and jacket were very well cut, and there was a diamond-tipped pin in his expertly tied stock. His blond hair was straight, and just brushed the collar of his jacket. Finally she looked into his eyes. They were a cold, cold green. Was this the Prankster?

“Your health, Miss Byron.” He raised his glass and drank. “I have sent for some supper. I intend to look after you. You’re far too valuable to me to be neglected.”

Valuable? For a moment she wondered if he wanted to employ her mathematical skills, but his next words disabused her.

“I can see you are your father’s daughter. You are brave, if not as beautiful as he was.” He smiled, but she did not sense any warmth. His speech and manners marked him as one of the gentry, but she’d never seen him before. He went on, “How much, I wonder, is Miss Byron worth? What do you say, my friends-in-evil?” Now he laughed and the other two joined in.

“A tasty piece,” the bearded man said. “Five hundred gold sovereigns.”

“At the very least. Add that to our pay-off for not blowing up St Paul’s and I reckon we might live comfortably — for a little while.”

“They were jewels. A ransom,” Ada said, finding her voice.

“I knew you’d solved it when I saw your coded message in the Personals.” The cold green eyes glittered. He stood up and leaned on the mantelshelf. “The poetic quotation was not as apt as I would have expected, but confirmed your identity. You decoded my message with help from Mr Babbage — my men have told me how you visit him. Now all that needs to be done is give the location where our ransom should be placed. I’m sure Mr Babbage can manage that alone.”

“I still don’t see why we need her.” The younger man who’d grabbed her on the jetty jerked his thumb at her. “I say she’s a liability. The ransom for the cathedral is enough.”

“Enough!” The blond man spoke quietly but with such venom that the other two men shrank back. “Nothing is enough, I’ve told you that before. I can never be recompensed for what I’ve been denied.” He looked at her, and she felt herself flinch. “I should have had the privileged life you’ve led — even more so. My father, the Duke, refused to acknowledge his by-blow, though. My mother told me everything. So I am making him and his kind pay — but on my terms.” He tossed back the last of his wine and went to the decanter for a refill. “As for why Miss Byron is here — I’ve sent a strong message: ‘Look at what I can do. “Look on my works, ye Mighty, and despair”. Ozymandias should be my middle name.’”

“Where did you learn to cipher?” Ada asked.

“Oh, I had a good education, the best. But I was bored, and found other things to interest me.”

“I have been tutored at home. And now,” she declared standing up, “I demand that you return me there.”

Her adversary flung his head back and laughed. “What if I decide to keep you? No one would be surprised. Mad George Byron’s daughter run off with an adventurer — only to be expected.”

Ada felt her throat grow tight. “My father,” she began, when suddenly she heard a voice from behind.

“Miss Byron, are you all right?”

“Robert!” He stood, pale and swaying a little, in the doorway to the second room.

“Get him,” the blond man ordered. As the other two men stood, Ada jumped up and ran to Robert.

“Leave him alone,” she said, standing protectively in front of him. “Haven’t you harmed him enough?”

“Not nearly enough,” growled the bearded man. “He should’ve died for his pains.”

“But someone did die,” Robert said. “That young man. You sent a message to the White Hart for him to come here. Why? Tell me that, before I follow him into the Thames.”

“He disobeyed me. He was supposed to hand my coded message to the speaker that night, to send the police searching after Radicals. At first he said he’d done so, but then we found out he was too frightened so he’d planted it on a policeman — you — to get rid of it. He’s learned his lesson now.”

“So that paper was never meant for me,” Robert said. “It was just chance. You chose that meeting to throw suspicion on the union men or the Irish.”

“Or even a latter-day Guy Fawkes. Now, get rid of him.” The blond man flicked his fingers and Ada braced herself, just as the sound of wood splintering, shouts and the blasts of whistles came from below.

“Quickly, out the back way. Bring her, kill him.”

Ada felt Robert’s arms take hold of her and together they struggled against the bearded man. She found a strength she didn’t know she possessed as she kicked out. But in the next moment the police had stormed up the stairs to their rescue and the blond man had shoved past them to escape through the back window.

“I have ordered up some meat and potatoes, and here’s some porter to drink.” Clark was smiling. Ada had heard him say several times, “A very good outcome indeed. Very good indeed.”

She sat beside Robert on one side of the grate, where the flames of a generous log fire gave as much light as the few candles around the room. Charles Babbage was on the other side, legs stretched out in front of him. They were in an upper floor private room of an eating house in the Strand. News had been sent to her mother that she was safe and would be home soon. She had been waiting for Clark’s restless energy to subside, but her questions could no longer wait for him to settle. She swallowed some of the bitter drink, her first taste of porter, coughed, and said, “You found me because of the message Rob — Constable Duckett sent?”

“It arrived at the same time Babbage did, with his news of your abduction and the final solving of the cipher — as well as the part played by his coded message in The Times. I should reprimand you, Mr Babbage, for acting alone and without sanction, but it had the desired effect. It drew our man out.”

“He thought Ada placed it. I’m sorry, Ada, for what happened,” Charles said.

“You asked my permission and I gave it.” She smiled at him.

Beside her, Robert stirred and coughed. He had a rug around his shoulders and the colour was returning to his face. “How did you know I was there?” she asked him.

Robert recounted his story of the young lad in the morgue and his returning memory. “The young man was punished all right. That villain, that Prankster, is a cruel man.”

“If you hadn’t posted extra men at the back of the building, Mr Clark, he might have escaped. Do you know his true name now?”

At last Clark sat down. “He has refused to give it, but in fact I recognized him from a State Assembly I attended in the summer. Henry de Bellfont. He was thrown out of the Assembly for making a fracas, and I learned his sorry history. No doubt he hatched his plot then. With apologies, Miss Byron, he is the bastard son of a Duke and, although his father did provide enough money for a good education, he has refused to acknowledge him publicly, for the sake of his legitimate children. Henry was sent down from Oxford University for underhand dealings and general misbehaviour, at which point the Duke stopped sending money altogether.”

“He felt he wasn’t getting what he was due — despite the rest of us having to earn our living, or our position in society,” Robert observed.

“He was cold and calculating,” Ada said, remembering his green eyes. “All he wanted was riches.”

“Pure self-justification. But he is very clever,” Charles said. “The codes were the work of a brilliant mind, only used for the wrong purpose.”

“Now,” Clark was suddenly serious. “I must ask each of you to keep all the details of this affair secret. As far as the police are concerned we have captured a thief and dealer in stolen goods. I have tried to protect Miss Byron’s identity.”

“Why a secret? Sir?” Robert asked. His tankard of porter was already drained.

“No good cause would be served by tarnishing those close to the king. We must preserve stability at all costs. And we don’t want speculation and gossip about Henry de Bellfont’s claims that he burned down Parliament and is capable of blowing up St Paul’s Cathedral.”

“They were empty threats?” Ada asked. “He didn’t have a hand in that fire? Or the collapsing buildings?”

“With that mind, he could plan anything,” Charles said, “but would he have been able to carry it through?”

“I shall make very discreet investigations, but I believe not. He seized on two events and pretended he caused them, so we would pay to save St Paul’s. I doubt he had any intention of blowing it up. Abducting Miss Byron was to add strength to his claims.”

“What about his trial? He might take the opportunity to boast of these deeds?” Robert said.

“We shall find another way of dealing with him,” Clark said. Ada saw a glint of ruthlessness in his eyes that made her wonder if Henry de Bellfont would ever reach a courtroom. Perhaps he’d be encouraged to go to Tasmania, or America. She caught Robert’s eye and saw he’d come to the same conclusion.

The door opened and two serving-women came in carrying trays of food. Once everything had been laid out, the porter topped up, and the women gone, Clark said, “I propose a toast. To Miss Ada Byron, without whose mathematical genius, ably assisted by Mr Charles Babbage, we would not have averted this crime.”

As the three men raised their tankards, Ada laughed, and felt herself go pink. She wondered if she would ever be so content again.