The poisoned teaplot: Polonium reading from hotel 'off the scale'

Radioactive teapot 'almost certainly used to kill Alexander Litvinenko was used to serve guests for several weeks after becoming contaminated'

Detectives investigating one of the murkiest international crimes ever to hit Britain - the murder of the former Russian spy Alexander Litvinenko - believe a quintessentially English teapot is at the centre of the web of intrigue.

Test results from the Millennium Hotel in Piccadilly, central London, were said by sources yesterday to show a teapot was "off the scale" in readings for polonium 210, the radioactive isotope used to poison the Russian exile at the hotel on 1 November.

Police yesterday refused to comment on the reports, which also said the teapot was not tested until the second week of December, six weeks after the poisoning. The still-radioactive teapot would have been used to serve potentially hundreds of other guests.

Mr Litvinenko's widow, Marina, confirmed that when her husband arrived at the hotel his tea was already poured. "He later said the tea wasn't very tasty, 'because it was cold'." It now appears that tea had been poured from a pot thatthe killer had managed to contaminate.

Police, understood to be "embarrassed" by the oversight in testing the teapot, now believe they have enough evidence to issue an arrest warrant for Andrei Lugovoi, a businessman and former KGB agent. In Russia, he yesterday dismissed accusations as "lies, provocation and government propaganda by the UK." The Russian constitution does not allow extradition for alleged crimes committed abroad.

On his death bed, Mr Litvinenko claimed that President Vladimir Putin and the Kremlin had orchestrated his death because of his outspoken criticism of Russia's leadership.

It was initially thought Mr Litvinenko, 43, had been poisoned during a meeting with his Italian contact, Mario Scaramella. The Itsu Sushi bar did show traces of polonium 210, but not where the two men sat. He had met Mr Lugovoi in October at the sushi bar, where it is believed poisoning was first attempted.

Hotel rooms Mr Lugovoi occupied in London were contaminated with polonium 210; traces were also found at the Arsenal stadium where he had watched a matchthe day Mr Litvinenko was poisoned and on the plane Mr Lugovoi boarded for a flight to Moscow.

If the police have got the right man, the question is whether he acted out of personal antipathy or was obeying orders. Some reports yesterday claimed police have concluded the killing was "state-sponsored". A spokesman for Mr Putin, however, said: "Russia has not done it and it is absurd even to think about it."