Litvinenko's widow appeals for inquest funding
The widow of Russian dissident Alexander Litvinenko has appealed for help with legal costs at his inquest.
Marina Litvinenko fears her costs will run into six figures and the inquest will last months.
She said she was prepared to do whatever it took to find the truth about the "unprecedented act of nuclear terrorism" that killed her husband.
Mr Litvinenko died in 2006 after he was apparently poisoned with the radioactive polonium-210 in London.
He had been an agent of the KGB and of its successor, the Russian Federal Security Service (FSB).
The man named by the UK authorities as the main suspect, ex-KGB and Russian government bodyguard Andrei Lugovoi, is willing to speak to the inquest by video link - but not to be questioned - according to the Russian news agency Interfax.
Mrs Litvinenko says her appeal for funds is justified by the resources available to her "adversaries".
"To judge from inquests of similar complexity, such as those into the deaths of Princess Diana and the victims of the 7/7 bombings, these hearings may last weeks, if not months.
"At the very least, my legal costs are likely to run into six figures.
"In these proceedings the evidence collected by the Metropolitan Police will be weighed against the story presented by Sasha's [Alexander's] accused murderer and his sponsors, with the unlimited resources of the Russian state at their disposal.
"I am sure that my legal team is the best in the world, but the reality is that compared to my adversaries I am severely constrained. This I why I am appealing to the public for help."
Inquest coroner Dr Andrew Reid is asking the Metropolitan Police and the security and intelligence agencies MI5 and MI6 to carry out further inquiries.
He deferred a decision last week on whether the inquest should be referred to a senior judge but said the inquiry into the 43-year-old's death should be wide-ranging.
Andrei Lugovoi has said he was not informed officially about the coroner's hearing, according to Interfax.
"My lawyers heard about it by chance and made a statement there," he was quoted as saying.
"I told my lawyers that, if necessary, I would be ready to provide explanations. This could involve a video link as well. Contrary to some media reports, there was no talk of me agreeing to be questioned."
Britain's relations with Russia soured after the murder of Mr Litvinenko, who had accused Russian security services of carrying out terror attacks to help bring Vladimir Putin to power.
The Russian authorities have repeatedly refused to send Mr Lugovoi to face trial in the UK.
Russian president Dmitry Medvedev insisted during Prime Minister David Cameron's visit to Moscow last month that Mr Lugovoi - now a Russian MP - would never be extradited to Britain.
Former director of public prosecutions Lord Macdonald QC said earlier this month he had the "gravest suspicion" that Moscow was involved in planning the murder.