Britain's Sun newspaper reports more confirmation that Alexander Litvinenko was struck down by a KGB assassin: the poison was laden with radioactivity and a high-ranking Russian official "cannot exclude the possiblity" of their involvement.

A FORMER Russian spy may have been poisoned with radioactive thallium at a London restaurant, a medical expert said. John Henry, a toxicologist treating Alexander Litvinenko, says the former KGB man may need a bone marrow transplant. He said: "The thallium is the least of it - the radioactivity seems more important. In terms of thallium, I do not think I have see a worse case of this. It is too early to say how long it will be before he's out of danger. He is very ill at the moment." Prof Henry said it was likely the poison had been swallowed. Scotland Yard's counter-terrorism unit is leading the hunt for the culprits.

A top Moscow politician has admitted Litvinenko may have been poisoned by the KGB. Viktor Ilyukhin — deputy chairman of the Russian parliament’s security committee — declared: “I can’t exclude that possibility.” He said of the dad of one, whose food is feared to have been spiked at a sushi bar: “That former KGB officer had been irritating the Russian authorities for a long time and possibly knew some state secrets. “So when our special services got the chance to operate not only inside but outside the country, they decided to get rid of him.”

Litvinenko, 44, is continuing to fight for life at London’s University College Hospital — guarded by armed police. He was in intensive care, with medics putting his chances of survival at 50:50. Litvinenko is able to talk and make jokes, but his condition remains serious in intensive care. Shocking pictures taken yesterday and released by his family showed the appalling effects of the highly-toxic chemical thallium. Litvinenko was pictured pale and weak in his hospital bed — his hair all gone.

Since then coverage of the poisoning in the mainstream media has been confined to a small number of outlets.

TV silence

Most noticeably for a media landscape dominated by television, Russia's three main TV networks seem to have steered clear of the story.

There appears to have been no mention of Mr Litvinenko in any of the main news bulletins or discussion programmes on state-controlled Channel One and Rossiya, nor on NTV, which is owned by the energy giant Gazprom.

Brief reports were, however, broadcast on the corporate-owned Ren TV channel and the business channel RBK TV.

The lack of television coverage came as no shock to Ekho Moskvy's editor-in-chief, Alexei Venediktov.

"It's not at all surprising that there's silence on television, it's understandable," he told listeners to his phone-in programme on Sunday.

The launch of an investigation by British police had led to "confusion" in the Russian authorities, he said.

'Key milestone'

Ekho Moskvy is the only mainstream Russian broadcaster to have aired regular reports on Mr Litvinenko's poisoning.

Since the British media latched onto the story on Saturday, the station has aired comments from another prominent Kremlin critic to have been granted asylum in Britain, Chechen rebel envoy Akhmed Zakayev, as well as Alex Goldfarb, a friend of Mr Litvinenko who helped him with his asylum application six years ago.

Earlier, Ekho Moskvy commentator Yuliya Latynina had spoken of the likely fallout from the case.

"This is a fairly key milestone, which undoubtedly alters the image of Russia in the outside world," she said.

Press coverage, meanwhile, has been minimal, with most papers ignoring Mr Litvinenko's ordeal.

The only title to have dealt with the story in detail is the Kommersant broadsheet, which carried its own report as well as comments from a number of Russian politicians and former security service officers.

The paper also quoted the exiled Russian tycoon Boris Berezovsky, another fierce critic of the Kremlin, who visited Mr Litvinenko in hospital on Friday.

For more insights, check out the scathing analysis of Edward Lucas in the Daily Mail (he writes: "The attempted murder of Litvinenko forms part of a grim pattern of intimidation. At home and abroad, enemies of the Kremlin tend to die in mysterious circumstances.").

To watch a video of Litvinenko speaking out against Putin over the Politkovskaya assassination, click here.