Oligarch Boris Berezovsky told the High Court today that it was "outrageous" to claim he was responsible for the horrific death of his friend Alexander Litvinenko by radioactive poisoning.
"I have been portrayed as a man whom people should fear," he said. "This affects my relationships with everyone who is not already a close personal friend."
The 63-year-old businessman was giving evidence in his libel action in London over a claim in an April 2007 broadcast on the Russian state-owned TV channel RTR Planeta that he was behind the 2006 killing.
"I had absolutely nothing to do with his murder and I have co-operated fully with the police in the course of their investigations. I even voluntarily gave an interview to the Russian investigators."
Mr Berezovsky told Mr Justice Eady that Mr Litvinenko, who he knew as Sasha, had twice saved his life and their shared history as exiles and opponents of President Putin and the FSB security service had cemented their friendship.
He first met Mr Litvinenko, who was then working for the Federal Counterintelligence Service (later the FSB), in 1994, when he investigated an explosion in Moscow which killed Mr Berezovsky's driver and, a year later, Mr Litvinenko helped him in a stand-off during a police raid
"We shared a dramatic and dangerous history; he had helped me and I him, and, fundamentally, we shared the same enemy.
"Sasha was not interested in politics, so, on one level we were never close, but he believed in honour and upholding the law and I had enormous respect for him."
When Mr Litvinenko fell ill, he visited him several times and couldn't believe how dreadful he looked.
He was shocked by the diagnosis that he had ingested polonium, and fearful of its implications.
"It is difficult to express all the emotions I felt at that time; I lost a friend, but the circumstances of his death were so shocking that it was impossible simply to mourn that loss."
Mr Berezovsky said that his wife, Elena, cried when they watched the broadcast at home in Surrey.
"I am shown saying that if I dislike someone I will kill them; I don't in fact remember saying these words at all, but assuming the words have not themselves been doctored, it would have been an ironic or jocular remark given in response to a question which has been edited out; certainly not an expression of intent.
"That the words have been taken out of context and used to suggest I am a murderer is absolutely outrageous, and deeply offensive."
He said he felt the programme, which included an interview with a silhouetted figure named Pyotr, was deliberate propaganda to threaten his asylum status and his security.
"I was extremely upset to be accused so directly of killing my friend; since Sasha's death I had offered comfort to his widow Marina; I worried about her reaction."
He added: "I was also very concerned about the damage the allegations would cause to my reputation here generally; I was being portrayed as someone who was prepared to murder his own friend in order to save his skin and advance his political aims.
"Many ordinary Russian-speakers; that is to say, not only Russians, but people from Ukraine, Latvia and other Baltic states living in Britain are not political exiles like me and are not necessarily cynical about the accuracy of the news they hear from the Russian media; they are likely to believe what they hear."
Mr Berezovsky's counsel, Desmond Browne QC, has said that The Russian Television and Radio Broadcasting Company (RTR), which has never suggested that what it broadcast was true, had declined to take part in the proceedings.
It had left Vladimir Terluk - who Mr Berezovsky alleges is Pyotr - "to face the music on his own", unrepresented by lawyers.
The judge, who is sitting without a jury, is trying the issue of damages in relation to RTR and that of liability and damages in respect of Mr Terluk, who denies he is Pyotr and also pleads justification.