The Italian academic who met former Russian spy Alexander Litvinenko on the day he was allegedly poisoned has tested positive for radiation, it was disclosed today.
As the post mortem examination started on the body of Mr Litvinenko, it was revealed Mario Scaramella had tested positive for a significant quantity of the deadly radioactive toxin polonium 210, sources said.
He is the first person to test positive since Mr Litvinenko's death sparked a radiation alert.
"We are confirming that one further person who was in direct contact with Mr Litvinenko has been found to have a significant quantity of polonium 210 in their body. This is being investigated further in hospital," a spokesman for the Health Protection Agency said.
"There is likely to be concern for their immediate health," the spokesperson added.
A lawyer representing Scaramella said he was waiting for final results before making any comments. He declined to explain Scaramella's earlier statements that he was not contaminated, saying the tests were "complex".
The suspicious death of Litvinenko in London last month has heightened tensions with Moscow and sparked a police investigation that has found traces of radioactive material in 12 places and grounded aircraft in both countries.
It remains unclear if the traces in the planes came from couriers shipping the poison or people who may have been victims.
With 33,000 people believed to have travelled in the past month on planes suspected of being contaminated, British authorities have been forced to reassure the public that the health risks are tiny unless the poison is swallowed or inhaled.
Earlier, three pathologists wearing protective suits carried out a post-mortem on Litvinenko at the Royal London Hospital.
Litvinenko, a British citizen who became an outspoken critic of President Vladimir Putin after leaving Russia's secret service, accused the Russian president of ordering his killing. The Kremlin has denied any involvement and promised to help the British probe.
EU Commission President Jose Manuel Barroso voiced concern about the case. "We have a problem with Russia. In fact, we have several problems. Too many people have been killed and we don't know who killed them," he said on Thursday.
British media reported on Friday that scientists at the country's Atomic Weapons Establishment (AWE) had traced the source of the polonium to a nuclear power plant in Russia.
The head of Russia's state atomic energy agency Rosatom, Sergei Kiriyenko, told the government daily Rossiiskaya Gazeta that Russia produces only 8 grams of Polonium 210 a month. He said all of it goes to U.S. companies through a single authorised supplier.
Russian Foreign Minister Sergei Lavrov said Moscow had not received any formal inquiries from Britain about Litvinenko's death. "The ball is now in Britain's court," he said.
In a separate development, Russian doctors said they had identified no natural cause for an ailment afflicting former Russian Prime Minister Yegor Gaidar, who fell ill during a trip to Ireland the day after Litvinenko died.
British police ruled out any link with Litvinenko. "We are not linking these two incidents. There's nothing to suggest any links," said a spokeswoman for Counter Terrorism Command.