London (AFP) - Britain announced an inquiry into the death of Alexander Litvinenko on Tuesday, the Russian former spy who accused the Kremlin from his London deathbed of poisoning him with radioactive tea.
The move comes as London pushes for greater sanctions against Moscow over the downing of a passenger plane in eastern Ukraine, and is likely to anger the Kremlin and further chill relations between Britain and Russia.
The inquiry will be able to look at whether the Russian state was behind the mysterious killing of Kremlin critic Litvinenko in 2006, which outraged London at the time and plunged relations with Moscow into the deep freeze.
Prime Minister David Cameron's spokesman said there was "no link whatsoever" between the ratcheting up of international pressure on Russia over flight MH17 and the launch of the inquiry.
But it represents a major turnaround for the British government coming just months after it had resisted attempts to hold an inquiry on the grounds of protecting sensitive information about Russian and British intelligence.
"It is more than seven years since Mr Litvinenko's death, and I very much hope that this inquiry will be of some comfort to his widow," said Home Secretary Theresa May, the interior minister, announcing the probe.
May said the inquiry would specifically seek to identify "where responsibility for the death lies".
Litvinenko's widow Marina said she was "relieved and delighted" with the decision.
"It sends a message to Sasha's murderers: no matter how strong and powerful you are, truth will win out in the end and you will be held accountable for your crimes," Marina Litvinenko said.
"It has taken nearly eight years to bring those culpable for Sasha's murder to justice. I look forward to the day when the truth behind my husband's murder is revealed for the whole world to see."
She said that she too believed there was no link between the timing of the announcement and the tensions with Moscow.
"I do this not against Russia, not England, I do this for justice, I do this for truth... I'm definitely sure it was not taken because of [the MH17 plane disaster] - the decision to take a public inquiry would have been taken anyway."
- 'Cynicism, lies, treachery' -
Litvinenko, 43, an ex-agent in Russia's FSB intelligence agency who turned against his former masters, was poisoned with radioactive polonium-210 while drinking tea at a London hotel.
In a deathbed letter, Litvinenko said he believed Russian President Vladimir Putin was involved in his killing after he publicly criticised the leader, himself an ex-Soviet KGB agent.
British police have identified Russian spy-turned-lawmaker Andrei Lugovoi as the chief suspect and have issued an arrest warrant for his fellow former agent Dmitri Kovtun, but Moscow has refused to hand them over. They both deny involvement.
The inquiry will begin on July 31 and is expected to run until the end of 2015. Some hearings could be held behind closed doors to examine material which might jeopardise national security.
The British interior minister originally wanted to wait for the results of a separate inquest into the death, which would determine how Litvinenko came by his death but not apportion blame.
However, three High Court judges ruled in February that May must reconsider that decision, following a challenge by Marina Litvinenko.
May decided not to contest the ruling, and on Tuesday announced the inquiry.
It will be chaired by senior judge Robert Owen, who was in charge of the inquest, which has now been suspended.
In English law, inquests are held to examine sudden, violent or unnatural deaths. While they determine the place and time of death as well as how the deceased came by their death, they do not apportion blame.
Owen himself had called for a public inquiry, saying he could not hold a "fair and fearless" inquest because he was not allowed to see secret evidence about the Kremlin's alleged possible role in the killing.
He will be able to demand the production of witnesses and papers within British jurisdiction, including agents and documents from the security and intelligence services.
But he has no such powers in relation to evidence from Russia.
The inquiry will also not look at whether the British authorities could or should have taken steps which would have prevented his death.
"The advantage of having a public inquiry is that the material that could not be disclosed as part of the inquest can now be seen by the chair of the inquiry and he will be able to take it into account, although that material will not be publicly disclosed," solicitor Elena Tsirlina said.
Lugovoi told Russia's Interfax news agency that he would not participate in the inquiry, which he branded politically motivated.
"Cynicism, lies, treachery, underhanded. This is the only way I can describe the actions of the British establishment and the decision to hold a public inquiry," he said.