Alexander Litvinenko's widow Marina has said she was "pleased" with the conclusions of the inquiry into his death and has called on Prime Minister David Cameron to take action. The inquiry claimed President Vladimir Putin 'probably' approved the Russian intelligence operation to murder ex-KBG agent Litvinenko in 2006. Litvinenko, 43, an outspoken critic of Putin who fled Russia, died after drinking green tea laced with the rare radioactive isotope polonium-210 at London's plush Millennium Hotel.

An inquiry led by senior judge Robert Owen found that former KGB bodyguard Andrei Lugovoy and fellow Russian Dmitry Kovtun carried out the poisoning as part of an operation directed by Russia's Federal Security Service (FSB), the main heir to the Soviet-era KGB.

Marina Litvinenko said in front of the High Court: "In this inquiry report into the murder of my husband Sasha Litvinenko, Sir Robert Owen found as a fact that Mr Lugovoy and Mr Kovtun deliberately administered polonium 210 to Mr Litvinenko intending it would kill him. He was quite sure that Mr Lugovoy and Mr Kovtun did so under the direction of others."

"I am of course very pleased that the words my husband spoke on his death bed when he accused Mr Putin of his murder have been proved true in an English court with a high standard of independence and fairness."

Marina added that she wants the British PM to act: "But now it is time for David Cameron, I am calling immediately for exclusion from the UK of all Russian intelligence operatives, whether from the FSB who murdered Sasha or from other Russian agencies based in the London embassy. I am also calling for the imposition of targeted economic sanctions and travel bans against named individuals including Mr Patrushev and Mr Putin."

The inquiry concluded: "Taking full account of all the evidence and analysis available to me, I find that the FSB operation to kill Mr Litvinenko was probably approved by Mr Patrushev and also by President Putin."

The Kremlin has always denied any involvement. The death of Litvinenko marked a post-Cold War low point in Anglo-Russian relations, and ties have never recovered, marred further by Russia's annexation of Crimea and its support for Syrian President Bashar al-Assad.