Ex-Russian spy may have ingested radioactive poison

LONDON, Nov 21 (Reuters) A former Russian spy fighting for his life in a British hospital may have been given poison laced with a radioactive substance to render it more lethal, the toxicologist treating him said today.

Russia has dismissed as ''nonsense'' claims its agents poisoned former spy Alexander Litvinenko, 41, a persistent critic of President Vladimir Putin. Friends say they believe he is the victim of a Kremlin-backed plot.

He is now in intensive care in a London hospital, suffering from poisoning with thallium, a chemical element which can cause a slow, painful death over weeks, even with treatment.

Britain's anti-terrorism police are investigating the case, which could have far-reaching diplomatic consequences. If Moscow were found to have had a hand in the poisoning it would be the first incident of its kind in the West since the Cold War.

Questioned at a news conference, British Foreign Secretary Margaret Beckett said she had not raised the case with Moscow.

Russia's SVR spy network repeated Moscow's denial of blame.

''There is absolutely no interest for us in occupying ourselves with such activities. Of course everyone has worth, but this person is not worth enough... to poison the atmosphere of warm relations between Moscow and London,'' SVR spokesman Sergei Ivanov said. ''May God give him health.'' Toxicologist John Henry, who is treating Litvinenko, said he now thought the thallium may have been in a more deadly radioactive form.

''Mr Litvinenko has got some symptoms consistent with thallium poisoning, and he has also got symptoms consistent with some other type of poisoning -- so it's not 100 per cent thallium,'' Henry told reporters outside the hospital.

''It could be radioactive thallium.'' Litvinenko has said he fell ill three weeks ago after meeting a source at a London sushi restaurant while studying the slaying of journalist Anna Politkovskaya, another Putin critic gunned down at her Moscow apartment last month.

POISON SWALLOWED Henry said Litvinenko apparently swallowed the poison.

He said doctors may never know the exact composition of the poison. ''If it was a radioactive poison with a short half-life, it may have gone.'' He said Litvinenko was very ill and it was too early to say whether he would survive. ''At the moment he is not getting better, but he is holding up.'' Alexander Goldfarb, a Russian dissident and close friend of Litvinenko, repeated his claim that Litvinenko was poisoned in a ''Kremlin-backed operation of Russian intelligence services''.

In Moscow, communist deputy Viktor Ilyukhin told Reuters many different versions were circulating about the poisoning.

''I don't rule out that Russian special services had had enough of the talkative Litvinenko,'' Ilyukhin said.

Ilyukhin also said Putin's enemies could be maximising bad publicity to discredit him and the Kremlin.

Litvinenko, now a British citizen, co-authored a book in 2002 entitled ''Blowing up Russia: Terror from Within'', in which he alleged Federal Security Service agents co-ordinated apartment block bombings in Russia that killed more than 300 people in 1999.

The bombings, which authorities blamed on Chechen rebels, led to a shift in public opinion in Russia, affording Putin as prime minister popular backing for his decision to move troops into Chechnya. Weeks later he succeeded Boris Yeltsin as president.

REUTERS SP KP2240