The poisoned Russian spy breathed defiance at the Kremlin as the effects of a mystery cocktail pushed him towards his death last night. “I want to survive, just to show them,” Alexander Litvinenko said in an exclusive interview given just hours before he died. Too weak to move his limbs and visibly in great pain, the former Russian intelligence officer suggested that he knew he may not win his struggle against the lethal chemicals destroying his vital organs. But he said the campaign for truth would go on with or without him. “The bastards got me,” he whispered. “But they won’t get everybody.”

Mr Litvinenko, 43, uttered his last defiant words to Andrei Nekrasov, a friend and film-maker, who had visited him in University College Hospital in London every day this week. Last night Mr Nekrasov described the extraordinary scenes in hospital, where one ward looks like a scene from The Godfather. “Sasha was a good-looking, physically strong and courageous man,” Mr Nekrasov told The Times. “But the figure who greeted me looked like a survivor from the Nazi concentration camps.” Moments after he saw his friend pass away, Mr Nekrasov said: “I have been through a few things in Russia and Chechnya, but this is one of the most horrible crimes I have witnessed in my my life.” “It was sadistic, slow murder. It was perpetrated by somebody incredibly cruel, incredibly heartless. It had no meaning whatsover.”

Although Mr Nekrasov had seen Mr Litvinenko sometimes more than once a day, Tuesday was the last occasion on which his friend could communicate properly. Yet in his final remarks, the former spy remained defiant in his battle against President Putin and the Russian security services. He also managed a joke at his own expense, suggesting that his poisoning was proof that his campaign against the Kremlin had targeted the right people. “This is what it takes to prove one has been telling the truth,” he said. He was referring to allegations he made in a book, The FSB Blows up Russia, which accuses the Russian security services of causing a series of apartment block explosions in Moscow in 1999 that helped to propel Mr Putin into the presidency. Last night in Moscow, Andrei Lugovoi, the former Kremlin bodyguard who has been accused of carrying out the poisoning, told The Times that he was not involved and that he was prepared to travel to London to prove his innocence.

Doctors remained baffled about what Mr Litvinenko ingested on November 1, at one of two meetings with Russian contacts. Geoff Bellingan, director of critical care at University College Hospital, said that doctors were now convinced that the cause was not a heavy metal such as thallium, as originally suspected. Nor had he swallowed any mystery objects. “Radiation poisoning is also unlikely,” he said.

Andrea Sella, a chemistry expert at University College, said that it had become increasingly difficult to identify the poison. “They have to find some unspecified poison. They don’t know whether it is a single substance or a mixture.”

Mr Nekrasov revealed that Mr Litvinenko’s British citizenship had come through on the day of a service at Westminster Abbey for Anna Politkovskaya, a friend and critic of the Kremlin murdered in Moscow.

“We discussed the likelihood of another killing. Sasha warned me not to go back to Russia because it was too dangerous,” Mr Nekrasov said. “Very sadly he turned out to be the next victim, attacked in the perceived safety of Central London.”

Last night, Oleg Gordievsky, a KGB agent who defected to Britain, told Sky News: “It’s very sad news because he was a hero to Russia and a hero to Great Britain. He loved Britain as much as he loved Russia.”

An aide to Mr Putin said: “Of course it’s a human tragedy. A person was poisoned. But the accusations against the Kremiln are so incredible, so silly, that the President cannot comment.”

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