The former Russian spy Alexander Litvinenko was a "direct traitor" who would have been sentenced to death in Soviet times, his former commander in Russia's security service said last night.
Alexander Gusak, who once headed a secret unit described as a "death squad" by Litvinenko, said the former spy had committed treason by betraying other Russian agents to British intelligence officers.
The undercover agents allegedly went to Mr Gusak, once the head of the FSB, the successor to the KGB, to ask how they should respond, with one even offering to murder the ex-Russian spy who died last November after ingesting radioactive polonium.
Mr Gusak, who left the service in 1998 - the year that Litvinenko exposed a plot by the FSB to assassinate Boris Berezovsky - and who now works as a lawyer, was asked by BBC's Newsnight if the spy deserved to die. "I consider him a direct traitor because he betrayed what is most sacred for any operative - his operational sources," he said.
"His operational sources came to me and they complained that your [British] secret service officers had found them, and asked what to do. For that - and I speak as a lawyer - what Litvinenko did comes under article 275 of the criminal code.
"It's called treason. And there are sanctions; prescribed punishments. Up to 20 years in prison. But that's in accordance with the law."
But he went on to say that he was brought up on Soviet law. "That provides for the death penalty for treason - article 64," he said. "I think if in Soviet times he had come back to USSR he would have been sentenced to death."
Mr Gusak revealed that agents who believed their names had been passed on by Litvinenko asked for his advice.
"I'll tell you honestly, I didn't advise any of them to go and kill Litvinenko, though one of them did say: 'Listen, he's done you so much wrong - shall I bring you his head?"' he said.
In November, Mr Gusak claimed that Chechen separatists could have killed the former spy.
The former head of the secret unit confirmed Litvinenko's claims that a superior officer in their secret unit had ordered them to kill the Russian oligarch Boris Berezovsky in 1997. Litvinenko warned Berezovsky about the order and then organised a press conference where he and four fellow officers revealed the existence of the unit.
Mr Gusak said he did not believe the order to kill the oligarch was serious, but added: "If the director of the FSB, Nikolai [Kovalyov], had personally given me the order, I would have carried it out - without written instructions. I loved Kovalyov."
As Mr Litvinenko, 43, lay dying in hospital in London from radioactive polonium-210 last year, he accused Mr Putin of ordering his murder - allegations which the Kremlin strongly denies.Reuse content