The Guardian newspaper reported the inquiry could “find the Russian state liable for his death” in 2006 and said diplomats were urging Prime Minister David Cameron not to launch major sanctions in retaliation.
The inquiry’s chairman, judge Robert Owen, said even before the start of the hearings last year that he believed there was evidence of “a prima facie case as to the culpability of the Russian state”.
Russia, which is key to ongoing talks on the Syria conflict has condemned the inquiry as “politicised”.
Kremlin spokesman Dmitry Peskov shrugged it off on the eve of publication, saying: “This is not in the range of topics that are of interest to us”.
Litvinenko’s widow Marina has led a long campaign for an inquiry and told AFP in an interview last year that it was “the last thing I can do for him”.
“My struggle has been for the facts to be made public,” she said, adding: “For me it is just important to finally have an official explanation”.
– ‘Nuclear terrorism’ –
Litvinenko was allegedly poisoned at a hotel by a cup of tea laced with polonium-210 — an extremely expensive radioactive isotope only available in closed nuclear facilities — in a sequence of events which could have come from a Cold War thriller.
The ex-KGB agent turned freelance investigator and Kremlin critic publicly accused President Vladimir Putin of ordering his killing before he died in agony three weeks later on November 23, 2006.
Litvinenko’s killing caused widespread public outrage in Britain after radioactive traces were found at various sites around London and it was dubbed by the media as the world’s first act of “nuclear terrorism”.
The original police investigation led British prosecutors to demand the extradition from Russia on murder charges of Andrei Lugovoi, a former Kremlin bodyguard who had tea with Litvinenko at the Millennium Hotel in London’s upmarket Mayfair area.
Russia has refused to extradite him.
Lugovoi, who has since been elected to the Russian parliament as a member of the far-right nationalist LDPR party, has loudly protested his innocence.
The latest inquiry has focused less on Lugovoi and more on his friend and associate Dmitry Kovtun, a former Soviet soldier and businessman who was also at the meeting in the hotel with Litvinenko.
The inquiry heard that Kovtun told a friend of his from Germany that he had some poison and needed a contact for a cook in London to kill Litvinenko.
Kovtun, who worked in a restaurant in Hamburg for several years, also allegedly told his friend that Litvinenko was “a traitor with blood on his hands”.
– Lead-lined coffin –
Britain announced the inquiry in July 2014, just days after the downing of a Malaysian passenger jet over eastern Ukraine — a tragedy blamed on Russia’s involvement in the conflict in the region — in what was seen as a way of punishing Russia.
Litvinenko served in the KGB during Soviet times and then in its successor agency, the FSB.
In 1998, he and other FSB agents gave a press conference in Moscow accusing the agency of a plot to kill Boris Berezovsky, an oligarch who helped bring Putin to power but later turned against him.
Litvinenko was tried for abuse of power and although acquitted in 1999 he fled Russia, apparently through Georgia and Turkey with a fake passport.
He was granted asylum in Britain and later became a British citizen, also converting to Islam after befriending exiled Chechen separatist leaders.
He was buried in a London cemetery with Muslim rites in a lead-lined coffin to prevent radiation leakage.