Russians: The Oligarch

In Russia, meanwhile, the media is accusing Britain of being in a panic. Both the government and the state-controlled news put forward various alternate theories - either that he accidently poisoned himself while trying to sell the nuclear isotope to Chechen rebels, or that Litvinenko's associate, the fugitive oligarch and reputed mafioso Boris Berezovsky (left), was behind it in an attempt to destabilize the Russian government.

Berezovsky, once Putin's ally, is now one of his fiercest critics. He, along with former Chechen rebel commander and foreign minister of the Chechen government in exile Akhmed Zakayev (left), were part of Litvinenko's inner circle in London.

Here's Berezovsky's timeline:

1989

With Perestroika under way Berezovsky enters the business world. He will go on to become Russia’s first billionaire. He was rumored to be targeted by the Russian mafia due to his connections with Chechen mafia.

1994

Berezovsky survives a car bomb attack. The FSB assigns Litvinenko to investigate, and the two become friends.

1996

Berezovsky forms a group of oligarchs, the Big Seven, to bankroll Yeltsin’s election campaign. The Big Seven controlled most of the media outlets, awhich become dedicated to "all Yeltsin all the time".

Berezovsky becomes engaged in peace negotiations with Chechnya, and formed sympathetic ties with Chechen rebels.

In a Forbes article Godfather of the Kremlin? American journalist Paul Klebnikov (left) portrays Berezovsky as a mafia boss who had his rivals murdered. Berezovsky sued the magazine, which then retracted the claims.

Klebnikov is assasinated in Moscow in 2004.

1998

Litvinenko goes public with claims that the FSB order him to assassinate Berezovsky

1999

Berezovsky elected to Duma. Although he supported Putin’s campaign for the Presidency, he was opposed to the Second Chechen War.

2000

Berezovsky sets up Liberal Russia party. Putin begins investigating him for corruption, and Berezovsky escapes to London. Alex Goldfarb (left), Berezovsky's right-hand man and Chair of his International Foundation for Civil Liberties, helps Litvinenko and his family flee Russia. Litvinenko moves into Berezovsky's north London house.

2003

Berezovsky goes into business with Neil Bush, the younger brother of the US President.

Berezovsky formally changed his name to Platon Elenin

Berezovksy claims that Chechen separatists have acquired a portable nuclear bomb, and only lack one “minor detail. Recent speculation is that polonium-210 could be that minor detail.

2005

Berezovsky helps finance Ukraine’s Orange Revolution and the campaign of president Viktor Yushchenko.

2006

Litvinenko becomes mysteriously ill (left). Goldfarb acts as spokesman during the affair. Litvinenko eventually dies from radiation poisoning, and Berezovsky accuses Putin of murder.