Knife Edge

6.58 P.M.

'I didn't make a mistake,' said PC Nigel Butler, forced to raise his voice to make himself heard over the din of the helicopter's rotors. 'I heard the message clearly from DS Mason.'

Butler shifted in his seat, both hands gripping the HK81 rifle.

His palms felt sweaty against the wood and steel of the weapon. Not just because the evening was fairly humid but because he was nervous.

He hated flying at the best of times. A plane was bad enough but the helicopter was even worse.

When it had taken off that afternoon, with the minimum of forward movement then straight up into the air, he'd struggled to retain control over his stomach and ever since they'd been in the air he'd felt queasy.

The Lynx was cruising at about one thousand feet and Butler was seated where the co-pilot would normally have sat. Unfortunately for him, he had an excellent view through the large windscreen of the chopper and also, when he inadvertently looked down, through the glazed nose panel.

Beside him, the pilot, Jim McBride, guided the helicopter skilfully through the air, occasionally taking it lower. So low, it seemed to Butler, that they were destined to crash into some of the capital's taller structures, but the big Scot flying the Lynx merely smiled as he saw the expression of panic periodically flash across the policeman's face.

Behind Butler, also armed with an HK81, Duncan Clark glanced into the cockpit, eyes roving over the banks of instruments which McBride dealt with almost nonchalantly. Lights flashed on and off and, throughout the flight, the muted sounds of voices floated back to him as McBride received instructions via his headset.

Above it all, the constant roar of the huge rotor blades dominated everything as they cut through the sky.

'How long before we reach Liverpool Street?' Clark shouted.

'Three or four minutes,' McBride told him.

'And you're sure you heard the order clearly?' Clark persisted, touching Butler's shoulders.

'Yes. When Doyle gets to Liverpool Street he'll be tracked by plain-clothes men,' Butler began. 'They'll tail him to wherever Neville sends him. When he makes contact with Neville we'll be notified. We move in and shoot Neville. And we shoot to kill.'

They rode the escalator from the lower platform, standing side by side.

Doyle, his long brown hair swept back from the collar of his jacket, felt his face greasy with perspiration.

Lisa, still pulling at the loose thread on her sleeve, gazed around her, taking it all in. Then she looked up at Doyle and slipped her hand into his.

He glanced down at her, feeling her tiny hand inside his strong one.

She smiled up at him and he found himself pinned in the almost luminous brilliance of her eyes.

He managed a smile in return then he winked at her.

Do you reckon she'd still be smiling at you if she knew you were going to kill her father?

Doyle brushed a hair from his face.

It isn't her father. But she thinks it is. That's all that matters.

They stepped off the moving staircase, Doyle looking around the ticket hall. A flight of stone steps led up to the concourse itself.

They began to climb, Doyle deliberately slowing his pace so that Lisa could keep up with him.

She held his hand all the way up.

As they emerged on to the concourse, Doyle's eyes sought the public phones. There were four of them to the right and he headed towards them, Lisa keeping step with him.

Only when he actually reached the phones did Doyle release her hand.

All four were in use.

Doyle glanced at each user.

A youth in a blue Chelsea shirt and baggy jeans was talking animatedly into the mouthpiece of the first phone.

A young woman with a large suitcase beside her was at the second.

Then a middle-aged man who kept looking at his watch as he spoke.

At the fourth was a stunning Asian girl who was wearing a bright yellow jacket and the shortest skirt Doyle had ever seen. The garment, along with the black high heels she wore, drew even more attention to her shapely legs. He stood watching as she constantly lifted one foot from her left shoe, flexed her toes, then slid her foot back into the stiletto. She performed the movement with almost robotic precision and grace.

Aware of Doyle's prying glance, she turned so that her back was towards him.

He looked at his watch.

There was less than a minute before Neville was due to phone.

He'd get an engaged signal. As simple as that. He wouldn't detonate a bomb for that.

Would he?

Doyle licked his lips anxiously.

Time was almost up.

Pull them away from the phones. Do it now.

All of them?

The counter terrorist moved slowly from one foot to the other, the movement almost imperceptible.

Lisa watched him and giggled. To her it looked as if he was swaying gently back and forth like a tree in a breeze.

Doyle looked at his watch again.

Neville wouldn't detonate a bomb just because he got an engaged signal.

Can you be so sure? Do you want to risk it?

Doyle pulled the Beretta free (fuck it, this was becoming a habit) and held it in the direction of the four phone users.

'Get away from the phones, now,' he shouted.

The quartet seemed to turn simultaneously.

The youth in the Chelsea shirt dropped the receiver and ran.

The woman with the large suitcase screamed.

The man in the suit stood motionless, the receiver gripped so tightly in his hand that Doyle feared he would snap it in two.

The Asian girl's eyes bulged wildly in their sockets, her lips trying to form words but nothing would come out.

Other eyes turned towards the noise. Other eyes saw Doyle and the pointing gun.

'Get away from the phones,' he ordered.

'Please don't,' the woman with the suitcase blubbed. 'Take what you want.' She was pushing her handbag towards him.

'Just get away from the phone,' Doyle said, lowering his voice, glancing around, noticing that other people on the concourse were running towards exits in an effort to escape this long-haired madman.

Lisa looked on in bewilderment.

She could hear the screaming. She saw the looks of terror on people's faces.

And when she turned, she was the first to see two uniformed policemen running towards them.