Alexander Litvinenko's weeping widow appeals for funds to force inquiry into his death

Alexander Litvinenko: The former KGB agent died from polonium-210 poisoning in 2006 (PA)

The widow of a Russian dissident who died after being poisoned in London broke down in tears as she told how she was struggling to fund a fight to force a public inquiry.

Marina Litvinenko appealed to the British public for financial help so she could continue to search for "the truth" surrounding the death of former KGB spy Alexander Litvinenko seven years ago.

She wept as she told how she could be faced with a bill for at least £40,000 and lose "almost everything" if she continued a legal battle with the UK Government.

"I really want to get the truth," Mrs Litvinenko told reporters, after her latest round of High Court litigation in London. "I absolutely cannot just give up."

Mrs Litvinenko wants the High Court to rule that Home Secretary Theresa May was wrong not to order a public inquiry into her 43-year-old husband's death in 2006.

But she could be left with legal bills running into many tens of thousands of pounds if judges rule that Mrs May did nothing wrong.

She has told judges that she will make a decision on whether to continue her application for a judicial review by late Monday.

"I need to take some very serious decisions," Mrs Litvinenko told reporters, as she fought back tears. "I have 48 hours to decide."

Marina Litvinenko wants an inquiry to look into whether British agents failed to protect her husband

Her lawyer, Elena Tsirlina, said she needed help to continue the fight and added: "We are asking the people of this country for money."

Mr Litvinenko was poisoned with radioactive polonium-210 while drinking tea with two Russian men, one a former KGB officer, at the Millennium Hotel in Grosvenor Square in 2006 and died later.

A full inquest into his death has yet to take place - although the latest in a series of preliminary inquest hearings has been held in London.

Ms Tsirlina said Mrs Litvinenko did not think that in inquest alone was enough and added: "With just an inquest it will be reduced to a forensic case only."

Additional reporting by Press Association