Litvinenko remembered one year on

Walter Litvinenko was joined by his son's widow, Marina, and other family and friends outside University College Hospital in London.

They marked the murder of the outspoken Russian dissident by re-reading his deathbed statement, accusing President Vladimir Putin of complicity in the plot.

Speaking with barely contained anger in his voice, Mr Litvinenko accused Andrei Lugovoy of being the "chief executioner" in the polonium plot.

But he said: "The gangsters who poisoned my son in the Millennium restaurant here are even today trying to show the whole world that they can get away with anything.

"As a reward, the chief executioner of my son, Mr Lugovoy, has now been given a seat in the Duma. The main executioner, Mr Putin, is afraid to leave his position, as he wants to maintain his power in order to cover up this crime."

He added: "Western leaders and European leaders must take these things extremely seriously, because the gas and oil they buy from Russia may turn into something rather more sinister.

"I trust my son did not die in vain, and the truth and justice for which he was fighting will prevail in the whole of the world, including Russia."

Mr Litvinenko's friend, Alex Goldfarb, read out his deathbed statement, watched by billionaire supporter Boris Berezovsky.

He repeated the memorable words in which the exiled Russian told Mr Putin the "howl of protest" will echo in his ears forever. He said: "May God forgive you for what you have done, not only to me, but to beloved Russia and all of its people."