Alexander Litvinenko

Alexander Valterovich Litvinenko, intelligence agent: born Voronezh, Soviet Union 30 August 1962; married (one son); died London 23 November 2006.

Alexander Litvinenko was a middle-ranking Russian security service agent who knew he was risking his life by stepping out of the shadows to go public with accusations against the master of the Kremlin. For President Vladimir Putin, a former KGB agent himself, Litvinenko committed the ultimate betrayal.

Litvinenko, who has died in hospital in London after being poisoned, joined the KGB in 1988. He was a lieutenant-colonel in its successor organisation, the FSB, when he broke cover in October 1998 to accuse his superiors of ordering him to assassinate the businessman Boris Berezovsky.

The immensely wealthy Russian oligarch, who successfully claimed political asylum in Britain after fleeing fraud charges in Russia in 2000, fell out with Putin after the President turned on the men who had helped him to power in the twilight years of the Yeltsin era. Berezovsky has been an implacable political foe of Putin ever since.

Litvinenko went public in the most dramatic way possible, by calling a press conference in Moscow where he sat flanked by fellow agents clad in balaclavas. One can only imagine the reaction of the head of the FSB at the time, who happened to be Mr Putin.

Born in the city of Voronezh in 1962, Litvinenko had switched to the KGB from the Soviet military, which he joined after school. After working for KGB counter-intelligence, he was promoted to the Organised Crime Control Directorate, the FSB top secret unit investigating terrorism and organised crime, where he worked until his spectacular downfall.

In addition to implicating his bosses in the assassination bid against Berezovsky, he also accused them of using his unit to carry out contract killings, extortion and corruption. His allegations prompted the FSB to charge him with kidnapping businessmen and extortion. The case collapsed, but he was rearrested. He was facing a third court case when he fled to London in 2000, where a grateful Berezovsky rewarded him with a job in his security detail.

Once in the West, the former spy continued to speak out, publishing a book - Vyzyvayu Sebya na Dopros ("Called In for Self-Interrogation") - which lifted the lid on the FSB. He alleged that the security services had been behind the 1995 killing of the head of the ORT television station, Vladislav Listev, who was murdered in one of the most high-profile unsolved murders of the 1990s. Litvinenko said that he gathered evidence about the killing and took it to the prosecutor-general's office. According to Litvinenko, he was arrested for his pains, while the evidence was destroyed.

In 2002, Litvinenko co-authored Blowing up Russia: terror from within, in which he accused the Russian security services of responsibility in a series of deadly attacks on apartment buildings in Moscow. The attacks in September 1999, which killed 300 people, led to Putin declaring the second war on the rebellious Russian republic of Chechnya.

The attacks were officially blamed on Chechen militants, and Litvinenko was certainly not alone in questioning the official version. The Independent reported the accusations against the FSB in January 2000. A friend of Litvinenko, Andrei Nekrasov, made a film, Disbelief (2004), detailing the allegations, which Putin has described as "delirious nonsense". But the most prominent person to accuse the Russian security services of responsibility for the apartment block attacks was Berezovsky, who financed Litvinenko's book.

In May 2002, Litvinenko was convicted in absentia of abuse of office by a Moscow court and sentenced to three and a half years in jail.

The small band of political dissidents in London was growing, causing a major irritant in UK-Russia relations. A former Chechen actor and rebel commander, Akhmed Zakayev, claimed asylum in Britain in December 2002, as the Russians were demanding his extradition to answer charges over the Moscow theatre siege carried out by Chechen rebels. It took a year and a much publicised extradition case, in which Zakayev had the support of the actress Vanessa Redgrave, for the case to be rejected and for Zakayev to obtain political asylum. The Chechen and the former FSB agent were neighbours on the same street in north London.

Despite an assassination attempt in 2005, Litvinenko continued to write inflammatory articles criticising Putin in the Chechen press. The Chechen connection also brought Litvinenko into contact three years ago with Anna Politkovskaya, the fearless Russian journalist known for her investigative reports which exposed the Kremlin's role in atrocities being carried out on the civilian population in Chechnya. She survived an earlier poisoning attempt before being gunned down in the lift of her Moscow apartment block on 7 October - with the finger of blame, once again, pointing at the Russian security services.

With the West still in shock over her death, Litvinenko attended a panel discussion on 19 October, "The killing of Anna Politkovskaya - Russia's dirty secrets", held in London at the Frontline club, a journalists' forum. Litvinenko, one of the many Russians in the audience, stood up towards the end of the discussion and said:

I don't want to hide anything. Somebody asked who is guilty of Anna's death. I can directly answer you: it is Mr Putin, the President of the Russian Federation.

Litvinenko did not say what evidence he had for levelling such a charge. But he did say:

I am totally confident that only one person in Russia can kill someone of Politovskaya's standing in Russia, and that is Putin. A journalist of her level could not be touched without the sanction of the President himself. She was a political opponent and this is why she was killed.

Exactly 13 days later, he was himself the victim of a mystery poisoning, which he was convinced was the work of the Russian secret services.

Anne Penketh