A Very Expensive Poison: The Definitive Story of the Murder of Litvinenko and Russia's War with the West

7 Ruslan and Lyudmila ^{Mayak nuclear complex, Ozersk, Russia, 1952–2006}

Every good Russian student knows the beginning of Alexander Pushkin’s much-loved mock-epic poem Ruslan and Lyudmila. It concerns a young prince, Ruslan, whose bride Lyudmila is seized from him on his wedding night by an evil dwarf, Chernomor. To get her back, Ruslan has to go on a knightly quest. Along the way he defeats a rival suitor. He meets a giant talking head and finds a golden sword.

The dwarf, meanwhile, tries in vain to woo Lyudmila, his prisoner. She manages to disappear using an enchanted hat. There is fighting. Ruslan grapples with Chernomor as they fly through the air. He later rescues Kiev from enemy attack. And there is a happy ending, with a little help from healing water and a magic ring.

The poem begins in a translation by Peter France:

Published in 1820, the mock-heroic fairy tale made the young Pushkin famous. He started writing it at the age of seventeen, a student at the lyceum near St Petersburg. He finished it three years later, a junior official at the ministry of foreign affairs. The poem is playful, luminous, sparse and strange. Pushkin admired Lord Byron; Ruslan and Lyudmila has witty and colloquial touches reminiscent of the British poet.

It is also a very Russian work. It blends elements from Russian folklore and ordinary life; as well as a fantasy garden there is a scene in a bathhouse. It’s subtle, too. Pushkin both enters into this fairytale universe and simultaneously stands outside and coolly assesses it. The low-tonality vowels of the opening have a haunting quality. What emerges is a new and vibrant literary language.

In the Soviet Union every educated citizen read Pushkin’s epic verse at school. So, it was unsurprising that scientists working at a Soviet nuclear facility deep in the Urals decided to call two of their nuclear reactors there ‘Ruslan’ and ‘Lyudmila’. The names were playful, half-nodding towards the strange and magical world of nuclear science. ‘Ruslan’ and ‘Lyudmila’ was also a lively, if ghoulish, shorthand – a way of referring to the clandestine work that went on inside the guarded perimeter fence. The Mayak complex was top secret, like other state institutions engaged in the assembly of nuclear weapons. What better way of defusing Mayak’s threat than jolly familiarity? In Russian, mayak means ‘lighthouse’, humorous given its invisibility.

The two reactors were built at the tail end of the Soviet Union. Ruslan is a pool-type light water reactor that has operated since 1979, undergoing a major overhaul in 1998–9. Lyudmila is a heavy water reactor that has been in operation since 1988. Lyudmila is bigger, with a power of 1,000 megawatts.

The Mayak complex sprang from the Cold War, and the post-1945 nuclear arms race between the world’s two superpowers, the US and the Soviet Union. After the American atomic bombings of Nagasaki and Hiroshima, Stalin accelerated the Soviet nuclear programme. The nuclear physicist Igor Kurchatov directed research, while Lavrenty Beria, head of the NKVD secret police, was put in charge of efforts to steal nuclear secrets from the US, Britain and Canada.

These efforts worked. The Soviets were able to recruit a network of agents from among the scientists designing the US atomic bomb in Los Alamos, New Mexico – Robert Oppenheimer, Enrico Fermi, Leo Szilard. In Britain, Donald Maclean, part of the Cambridge spy ring, told Moscow that the British were developing a uranium bomb too. It was an exhaustive international espionage operation that allowed Moscow to catch up.

Money and privileges flowed towards physicists and engineers who worked in this new and covert field. They included Andrei Sakharov, a gifted nuclear scientist and future dissident, and the physicists Yakov Zeldovich and Lev Landau. With many others, they successfully designed a Soviet H-bomb. A network of secret Atomgrads – closed cities – was built. These cities were dedicated to nuclear weapons research and development.

Mayak was located 43 miles (70 km) north-west of the city of Chelyabinsk and south of Yekaterinburg. The spot was chosen for its remoteness: it was in the geographic centre of Russia, far away from any front line, and protected by the Ural mountains to the west and Siberia to the east. In a mere eighteen months, Kurchatov built the USSR’s first plutonium production reactor, Anachka. Some 70,000 gulag labourers were used. More reactors followed. The site was based around the closed towns of Ozersk and Snezhinsk.

Many of the people who worked in Russia’s fledgeling nuclear industry had fled from war zones further west; they came from Belarus, Ukraine, Poland. Some were Jews who escaped the Nazis. Within a few years, Chelyabinsk was a booming industrial city, home to engineers, metallurgists and mathematicians. Another principal atomic facility was constructed at Sarov, 450 miles (725 km) south-east of Moscow near the Volga river. Sarov specialised in atomic weapons design and research. Sakharov worked there from 1950.

Officially, neither Mayak nor the Sarov complex existed: they didn’t appear on maps. Residents of closed cities weren’t permitted to leave for holidays until the 1950s. Sarov was codenamed Arzamas-16; Mayak Chelyabinsk-40, and later Chelyabinsk-65. They were closed to Soviet citizens, unless they had a good reason to be there. And, of course, off-limits to foreigners. This made them objects of allure for western powers. (In 1960, American pilot Gary Powers was photographing the Mayak atomic plant when his CIA spy plane was shot down.)

Soviet physics was a beneficiary of Stalin’s determination to match the US bomb. But there was a price. Little attention was paid to the environmental consequences of handling large quantities of fissile material. For example, radioactive waste water from Mayak was pumped out into small lakes nearby and the Techa river. The complex itself was the scene of mishaps and dangerous small leaks.

In September 1957, a cooling tank storing tens of thousands of tonnes of dissolved nuclear waste overheated and blew up. A cloud of radioactive material was set free. It contaminated over 300 square miles. Radiation was found in the Arctic Sea. It was one of the worst accidents of the nuclear age, on a par with the disasters at Chernobyl and Fukushima. In 1967, there was another catastrophe when Lake Karachay, used as a mid-level nuclear waste dump, dried out. Wind threw radioactive dust over a huge area.

The Soviet authorities responded to these accidents predictably, with denial and cover-up. (It took thirty years before Moscow acknowledged the Kyshtym disaster, as the 1957 Mayak explosion was known.) Troops were sent to evacuate some villages; soldiers fenced off the Techa river with barbed wire. But locals weren’t told what had happened: the leak was a state secret. In summer, children still swam in the river; farmers watered their cattle; women drew water from the wells; locals cut hay.

Gradually, the toxic legacy from Mayak became impossible for the Kremlin to conceal. People were dying. The disasters of the fifties and sixties exposed at least half a million to radiation poisoning. Symptoms were ubiquitous: intestinal illnesses, nose bleeds, food allergies. There were respiratory and skin problems. Cancers were rife. In some of the worst-affected areas, it was unusual for villagers to live beyond fifty. Some were dead at twenty. Chronic radiation sickness affected future generations.

Paula Chertok, who grew up in Chelyabinsk, and later emigrated to the US, recalls: ‘Nearly everyone I know from Chelyabinsk had cancer of one sort or another. Many had blood disorders. My mother’s best friend, a doctor, died young from leukaemia. Every woman I know had breast cancer. And we didn’t live in the villages, we lived in Chelyabinsk proper. The environment was utterly contaminated and we never knew a thing.’ She added: ‘We drank the water, played near the rivers and lakes.’

By the 1990s, the local population was still suffering from health problems, although the rules for visiting closed nuclear cities were somewhat relaxed. However, finding once-secret Snezhinsk is something of a challenge: the turn-off point to the town isn’t marked with any signs. A high and rather rickety wooden fence surrounds Snezhinsk, with a checkpoint manned 24/7 at its only exit and entrance. A sign in a field in Russian and English warns non-authorised visitors not to go any further.

Meanwhile, the state that built Mayak disappeared. The demise of the Soviet Union made life difficult for all Russians, but for scientists it was a disaster. State institutions were unable to pay their employees; some moonlighted as taxi drivers; others flogged their possessions on the street. Atomic-weapons laboratories continued to function and academic visitors noted a high level of professionalism still. But with the apparent end of the Cold War their future looked bleak.

It was a moment when Boris Yeltsin’s Russia believed in dialogue with the outside world; after all, Moscow was broke. In the US and Europe there were worries about what might happen to the former Soviet Union’s nuclear technicians. Worst-case scenario: the experts would go off and work in Iran, Iraq or Libya. Russian scientists were given grants. A team from Princeton University advised closed cities like Sarov on how to transform their production lines from nuclear bomb manufacture to non-weapons activity.

Some of these US–Russian initiatives worked. The secret Avangard laboratory in Sarov, for example, mothballed weapons production and began manufacturing civilian radioactive isotopes instead. It exported them to foreign markets, including America. This was, in effect, a job-creation scheme for the town’s shrinking scientific workforce, down from 4,800 employees in the 1980s to 3,300 by 2000.

Avangard became the only place in the world where one particular isotope was made. It had been manufactured there since 1952. Not many people had noticed. The quantities involved were tiny, the export market practically non-existent. But then the isotope was very rare and highly unusual: an intensely radioactive silvercoloured metal.

Polonium.

On 18 July 1898 Marie and Pierre Curie discovered polonium while experimenting with the mineral pitchblende. Pitchblende contained uranium. They repeatedly heated it, and dissolved the residue in acid. This process allowed them to isolate a new and unknown substance. It had extraordinary properties. It was 400 times more radioactive than uranium. Curie called this new element polonium.

The name was in tribute to Curie’s lost homeland, Poland, which hadn’t existed as an independent state since the late eighteenth century. Three imperial powers – Russia, Prussia and Habsburg Hungary – had partitioned it into non-existence. Curie’s family actively supported Polish nationalist movements; her father, a mathematics and physics teacher, was sacked from his job for pro-Polish sentiments. It would take two decades, strikes and street battles in Warsaw and Lodz in 1905, plus a world war, before Poland was reconstituted in 1918 as a sovereign territory.

Polonium was so rare it was impossible to make in any quantity. There were 100 microgrammes of polonium per ton of uranium ore. In the 1930s scientists found that under the right conditions they could manufacture polonium in a nuclear reactor. The technique involved irradiating another element, bismuth or Bi, by bombarding it with neutrons. (Specifically, Bi-209 absorbs a neutron and becomes Bi-210. It then beta-decays to Polonium-210, or Po-210.)

An isotope is a particular version of an element, depending on the number of neutrons. This resulting isotope was strange. Po-210 emits extraordinarily high levels of alpha particles, one of three types of radiation. A single gram produces 140 watts of energy, an enormous amount. Polonium is a source of much weaker gamma radiation. The element has a half-life of 138 days, which means that over this period half of the material will decay.

The right equipment can detect tiny quantities of polonium, so intense is its emission of alpha particles. It’s possible to detect amounts as small as a few picograms, one millionth of a millionth of a gram.

In the century since the Curies’ discovery, polonium never found much of a foothold in the real world. Nuclear states including the US, USSR, UK and France used polonium as a trigger for the first generation of nuclear bombs; it had a niche role in the Soviet space programme. In 1970, Moscow sent Lunokhod 1 – an ingenious space rover that looked like a giant bathtub on wheels – to the moon. (It’s still there.) During the lunar nights, Po-210 kept its components warm.

By the 1970s, polonium was more or less obsolete. Weapons scientists replaced it as a trigger with a more efficient tritium ‘gun’. State-run nuclear laboratories in the US, UK and Canada stopped making polonium. (In the 1950s and 1960s Britain produced it at civilian nuclear sites. According to the defence ministry in London, any surviving stocks would have completely decayed to Pb-206 – lead – by the early 1980s.) China abandoned polonium in the 1990s.

The only country that continued to produce it was the Russian Federation. The Avangard facility exported Po-210 on a commercial basis, for use in anti-static devices. The amounts involved were extremely small.

By the time Lugovoi and Kovtun came to kill Litvinenko in London in 2006, polonium was something of a forgotten chemical oddity. It was present on the periodic table, hanging in dusty chemistry classrooms, atomic number 84, found between bismuth and astatine, marked with a hazard sign.

Faced with what looked like a mini-nuclear bomb, a case with obvious political and diplomatic implications, and an international media frenzy, the British government sought expert advice on polonium. Where had it come from? Was it possible to buy polonium on the open market? How much would it cost? Did the UK have its own stockpiles? Could criminal gangs be involved? And just how dangerous was it?

One knowledgeable source was Norman Dombey, an emeritus professor of theoretical physics at the University of Sussex, set on a pleasant campus above the seaside town of Brighton. Dombey had published about a hundred scientific papers and was an authority on the nuclear weapons programmes of the UK, US and former Soviet Union. He also knew Russian. In 1962–3 he spent a year at Moscow state university on one of the first academic exchanges with the USSR, when he visited Soviet scientific institutions. He went back to Moscow in 1988 during Glasnost. He invited the nuclear scientist turned dissident Sakharov – by this point recalled by Mikhail Gorbachev from internal exile in Gorky – to the UK to collect an honorary degree. In 1992, Dombey visited the St Petersburg Nuclear Physics Institute. Subsequently he toured other physics institutions in Russia, as well as Armenia and Georgia, where professional scientific life had collapsed.

White-haired, approachable, lucid, modest, Dombey displayed a credibility that was enhanced by the fact that he was one of very few who predicted that Saddam Hussein didn’t have weapons of mass destruction. In September 2002, in the run-up to the Iraq war, he wrote an article entitled ‘Saddam’s Nuclear Incapability’. His thesis – there was no nuclear threat from Baghdad – contradicted the apocalyptic assessments coming from the Bush–Cheney administration in Washington, as well as from its ally in London, Tony Blair. Dombey, as history shows, was right.

The professor’s report on polonium – originally commissioned by Marina Litvinenko – was disturbing. The only comfort for investigators was that polonium was so intensively radioactive it was easy to track. The trail of those who brought it to London could be ‘easily established’, he believed.

The bad news was that what investigators were dealing with was an extremely hazardous substance – dangerous to handle in even milligram or microgram amounts, and requiring special equipment and strict control. Weight for weight, polonium was 2.5 x 10 to the 11 times as toxic as hydrocyanic acid.

Dombey’s suspicion was that the polonium had come from Russia. He also realised Litvinenko’s murder was not meant to be discovered. One version was that the use of polonium was showy: it sent a chilling message to Berezovsky and other émigré critics of the Russian regime. The other: that the isotope was the perfect undetectable weapon. Dombey inclined strongly to this second view. ‘It was meant to be a mysterious poisoning. That was because polonium was an alpha emitter which Geiger counters didn’t pick up,’ he said.

To be certain of the polonium’s origin, the professor had to make further inquiries. He wrote to senior nuclear officials in Moscow, the US, Canada and France. As he suspected, all countries other than Russia had ceased the manufacture of polonium. The only surviving polonium line was at Avangard in Sarov. Its director, Radii Ilykaev, confirmed the plant was exporting 0.8 grammes of polonium to the US a month, on a contractual basis.

Logically, there were only three ways of making polonium, Dombey reported. The first was to extract it from uranium ore, as the Curies did. The second was to irradiate a small sample of Bi-09 in a research reactor suitable for preparing isotopes. The third was to irradiate a large quantity of Bi-209 in a powerful high-flux reactor.

In his meeting with Lugovoi and Kovtun, Litvinenko drank 26.5 micrograms of polonium, it was established – or 4.4 gigabecquerels (GBq). This was an infinitesimally small amount, less than a grain of sand. A report by three radiation experts – John Harrison, Dr Nick Gent and Stuart Black – estimated that Litvinenko absorbed about 10 per cent of this dose – 0.44 gigabecquerels – into his bloodstream. It was more than enough to kill him

The actual amount put in the teapot, though, was larger – at least 50 micrograms, and probably 100 micrograms, including the undrunk tea left in Litvinenko’s cup and the remaining tea in the teapot.

It would be impossible to extract this amount of polonium from natural uranium ore, Dombey calculated. Nor could it be prised out of commercial supplies sent to America. You would need to buy or steal 450 anti-static devices containing polonium without anyone noticing. Moreover, the tiny amount of polonium inside was impossible to extract unless, as Dombey put it drily, those performing the extraction ‘wished to commit suicide’.

In the wake of Litvinenko’s murder, Russian officials said that any nuclear research reactor was capable of making the isotope. There are about thirty research reactors worldwide. But again the amount that could be generated was far smaller than the amount of polonium put in Litvinenko’s tea – mere picograms, at least 20,000 times smaller than the dose that killed him, via cell death in his body tissue and organs.

Dombey’s conclusions – made public in 2015 – were succinct. He wrote:

Dombey believed it was ‘highly unlikely’ that the reactor used to irradiate the bismuth was in Sarov. None of the reactors there had a sufficiently high neutron flux. Instead it began its journey to London from the Mayak facility near Chelyabinsk.

Litvinenko was undoubtedly Mayak’s most spectacular victim. But there were thousands of anonymous others in Chelyabinsk province and beyond who were consigned to agonising leukemias and premature deaths. Their suffering played out at home and in hospitals, largely unnoticed, beyond a small circle of family and friends, before an indifferent world.

The operation to kill Litvinenko was complex, covert and extra-territorial. It involved an esoteric nuclear poison, two hand-picked – if incompetent – assassins and a logistics chain that stretched from the Ural mountains via several intermediary points to the streets of London’s Mayfair.

It was also full of hazards. As part of his investigation, Dombey examined previous cases of polonium poisoning. In 1925, Nobus Yamada, a Japanese scientist who had been working at the Curies’ laboratory in Paris, fainted suddenly on his return to Japan. He had been handling polonium. Yamada died eighteen months later. In the summer of 1927, a Polish researcher, Sonia Cotelle, who had also been preparing polonium, suffered severe side effects. The Curies’ daughter Irene wrote that Cotelle was in ‘very bad health’, had stomach problems and had experienced ‘a very rapid loss of hair’. She carried on working for several years until a vial of polonium shattered in her face. She died two weeks later.

These were accidents, but Litvinenko’s death was deliberate. Given polonium’s rapid decay, the dose used to kill him must have been made in a relatively brief period before his killers travelled to London.

Dombey said: ‘Whoever poisoned Mr Litvinenko and brought polonium to Britain would only have done it if it had been tested in advance, because polonium is so radioactive that if they got their numbers wrong it wouldn’t work.’ He went on: ‘On the higher side it could have produced a major public health problem.’

With little data to go on, Dombey asked a colleague to check if there were any suspicious deaths in Russia with the same symptoms as Litvinenko’s? The colleague said there were. He mentioned two similar cases. The Russian press had featured both of them.

The first involved a Chechen guerrilla commander called Lecha Ismailov. Ismailov was captured, put in Lefortovo Prison, and tried. He got nine years. According to Akhmed Zakayev, Russia’s spy agencies put pressure on Ismailov to switch sides. He refused their offer to work for the FSB.

On the morning of his transfer from Lefortovo to a regular jail, the two people who had failed to recruit Ismailov summoned him for a friendly chat. They suggested he drink a farewell cup of tea. They also offered him a snack. Ismailov drank the tea. He began to feel ill after five minutes, as warders took him to his cell. He was moved to a hospital in Volgograd, where his Litvinenko-like symptoms – hair loss and massive blisters – bewildered doctors there. Twelve days later he was dead. His relatives told journalists they suspected Russia’s security agencies may have poisoned him.

The other possible precedent involved a figure from Vladimir Putin’s early years in St Petersburg, Roman Tsepov. In the 1990s, Tsepov worked as a bodyguard for Putin and for the city’s mayor Anatoly Sobchak. Allegedly, he was the liaison between politicians and the Tambov crime gang. Tsepov co-founded a private security company, Baltic-Escort. His partner was Viktor Zolotov, the future head of Putin’s personal bodyguard. According to some accounts, Zolotov was the president’s brutal enforcer and an individual of enormous physical strength.

Tsepov had friends in high places. And, unfortunately perhaps, he knew their secrets too well. In September 2004, he stopped by at the local FSB office for a cup of tea. He fell violently ill. He was admitted to Hospital No. 31 in St Petersburg, an institution that formerly treated the communist elite. Tsepov’s symptoms were unusual: vomiting and diarrhoea but also a catastrophic fall in white blood cells. He died shortly afterwards.

The investigative paper Novaya Gazeta quoted sources in the St Petersburg prosecutor’s office who said a post-mortem examination revealed ‘high quantities’ of radioactive contamination in Tsepov’s body. This wasn’t told to law-enforcement bodies. No cause of death was established.

Dombey’s report traced the source of the polonium to Mayak, in the form of irradiated bismuth. From Mayak it went to Sarov. But one link in the chain was missing. The polonium made on Sarov’s production line was in metallic form. Sealed in a special container, it was difficult to extract. The polonium used to kill Litvinenko, by contrast, was soluble.

According to Dombey, a ‘state organisation’ would need to convert the metallic polonium to soluble polonium. Only then could it be deployed.

That the KGB had its own specialist poisons laboratory was a well-established fact. Numerous former officers – some retired, some defectors – had confirmed its existence.

Pavel Sudoplatov, the former chief of Stalin’s foreign-intelligence service, who coordinated the atomic espionage operation against the US and Britain, mentions the lab in his 1994 memoir, Special Tasks. The poisons factory was set up in 1921. It went through several changes. Its core function – experimenting with poisons and other lethal substances on behalf of the state – remained the same.

Western intelligence experts believe its efforts were originally directed towards using poison on the battlefield. Tests were unsuccessful. The KGB concluded that poisons were better used to eliminate individuals.

The KGB had a track record of killing in Britain. Oleg Kalugin, a former high-ranking KGB officer and defector, now living in the US, said that the KGB’s poisons unit was involved in one of the most notorious murders of the Cold War. In September 1978, the Bulgarian dissident and writer Georgi Markov was waiting for a bus at Waterloo Bridge in London. He was on his way to his job at the BBC. Markov felt a sharp pain on his leg from what he thought was an insect bite; next to him he saw a man stooping to pick up a dropped umbrella.

Markov’s assassin had fired a pellet of ricin into Markov’s leg from close range. Four days later he was dead. According to Kalugin, the then head of the KGB, Yuri Andropov, agreed to a request from the Bulgarian security services to facilitate the assassination. Kalugin told Radio Free Europe: ‘Through the KGB laboratory we transferred the poison that was used in the umbrella. There was literally a milligram of poison, a small drop of ricin placed in a capsule at the tip of the umbrella.’

In the 1980s, the KGB’s lab was still operational. Litvinenko’s co-author Yuri Shvets, at the time an upwardly mobile KGB colonel, recalls meeting a laboratory staffer in Moscow. Against Shvets’s judgement, his KGB bosses had decided to use a truth-telling drug on his American source, codenamed ‘Socrates’. The secret KGB laboratory was at No. 1 Academician Varga Street, in south-west Moscow.

Shvets describes the use of speciality drugs as ‘among the most delicate of intelligence operations’. Documents relating to such operations were stamped with a ‘Special Importance’ classification. The Technical Operations Directorate of the KGB had to approve any use. The lab, Shvets wrote, produced a wide variety of drugs, including poisons, narcotics and psychotropic substances.

The drug used on ‘Socrates’ was SP-117 – concentrated alcohol dropped into his champagne glass. After ten minutes, the subject was drunk. At that point he was ready for interrogation. Shvets nicknamed the ‘small, portly’ lab worker who briefed him on the chemical side of the operation Aesculapius, after the Greek god of medicine. He noted that if this drug was number 117, the KGB’s arsenal probably included at least another 116 potions.

Political killings – of domestic opponents or troublesome exiles – were a hallmark of the Soviet Union and Russia from 1917 onwards. Under Yeltsin, these murders dwindled. But from 2000, prominent critics of the Kremlin once again began to meet mysterious deaths. The evidence of official complicity in these crimes was circumstantial. Defectors claim the KGB’s special poisons department was back in business, under a new and deliberately anonymous name, the FSB research institute.

The lab was in the same building as before. Its formal title is Nauchno-Issledovatelsky Institute No. 2 – Scientific-Research Institute No. 2. Or NII-2, for short. Photos of the institute show a squat, gloomy, beige edifice, dating from the Andropov era, built in impregnable isolation, with lights visible through its windows and a few scrawny trees.

According to locals, it’s a quiet spot. There is a guarded perimeter fence. When the building first went up in the 1980s, they assumed it was a hospital for injured Soviet veterans from the war in Afghanistan.

As well as Ismailov and Tsepov, there were others who appear to have been poisoned. The FSB admitted that it was behind a deadly poisoned letter sent in 2002 to Amir Khattab, a militant living in Chechnya. Journalist and Duma deputy Yuri Shchekochikhin died in July 2003. His cause of death was mysterious: his skin peeled off and his internal organs had swollen up. According to Dombey, radioactive thallium probably poisoned him. In 2004, Viktor Yushchenko, the pro-western presidential candidate in Ukraine, narrowly survived an assassination attempt. He was poisoned with dioxin; his face erupted in blisters.

Dombey’s report went to the heart of the row over who had killed Litvinenko and the question of state responsibility. In the days immediately after Litvinenko’s gruesome death, Kremlin regulatory officials told the media that Russia’s nuclear facilities were under tight control.

Sergei Kirienko, the head of Rosatom, the state agency in charge of Russia’s nuclear facilities, said that ‘control over production is very strict’. He added: ‘I don’t believe that someone stole from it.’ Boris Zhuikov, head of the radioisotope laboratory at the Nuclear Studies Institute, echoed this: ‘Everything connected with polonium production and application is controlled by governments … It is regulated and checked by many people.’

Dombey’s view was that such statements were true. Polonium was a state affair: made using reactor and production facilities belonging to the Russian state, supervised by the state. The facilities used to irradiate bismuth – a process involving highly radioactive materials – belonged to the state as well. These facts didn’t diminish the theory that the state was involved. Instead, they confirmed it, and led Dombey to conclude that the Russian state or its agents were responsible.

Litvinenko’s friends agreed. Goldfarb described the plot as an ‘interdepartmental effort’. Rosatom, formerly the atomic ministry, was an ‘extremely powerful’ organisation with its own hierarchy, Goldfarb said, pointing out that the agency’s chief Kirienko is a former prime minister. It was improbable the FSB would call him up and ask for a special delivery of polonium.

Something of this nature would require Kremlin authorisation. Since Rosatom officials stressed that no polonium had been withdrawn from their system there would need to be some sort of cover-up. ‘It would really be a very serious bureaucratic exercise,’ Goldfarb said.

As Yuri Felshtinsky put it: shooting someone in the head was one thing. Anybody could do that. Killing someone with a rare nuclear isotope was another. It would require collaboration between ministries and spy agencies as well as ‘coordination from the very top’.

All Scotland Yard had to do was to get the evidence.