The death of the former Russian spy Alexander Litvinenko, linked to radiation poisoning, has caused a public health alert in London.
After the discovery of highly dangerous radioactive polonium-210 in the dead man's body, the Health Protection Agency (HPA) called on anyone who visited the same places as Mr Litvinenko on 1 November to contact NHS Direct.
The HPA said that more than 450 people had called the helpline and that details of 18 people had been passed on to them.
As the BMJ went to press it emerged that three of the 18 were having tests at an unnamed clinic after reporting symptoms that might indicate radiation poisoning.
The test results are expected early next week. All three had had contact with either the London hotel or the sushi bar visited by Mr Litvinenko on 1 November.
The home secretary, John Reid, told the BBC that they had been referred as “a precautionary measure.”
The sushi restaurant in Piccadilly was this week being decontaminated. Parts of the Millennium Hotel in Grosvenor Square remained closed to the public pending safety tests, and checks were continuing at a number of places that Mr Litvinenko may have visited.
Mr Litvinenko died while in intensive care in London's University College Hospital on 23 November from heart failure, believed to have been caused by systemic effects of the radioactive poison.
On his deathbed the former spy claimed that the Russian president, Vladimir Putin, had ordered his assassination.
The exceptionally deadly and exotic nature of the substance that poisoned the Russian dissident, together with the public health risk it posed, also threatened to start a diplomatic row between London and Moscow.
The Northern Ireland secretary, Peter Hain, said a series of “murky murders” had now cast a shadow over the government of Vladimir Putin. Radiation experts said the poison would almost certainly have been prepared at a highly specialised facility.
Polonium-210 is a powerful emitter of α radiation, which at close range is the most destructive form of radiation.
The HPA stressed, however, that the poison is only hazardous when taken into the body—by breathing it in, by taking it into the mouth, or if it gets into a wound.
Tests are also being done at University College and Barnet General hospitals, which treated Mr Litvinenko, but radiation specialists stressed that the risks to health workers were probably low.
William Gelletly, a professor of physics at the University of Surrey, said, “It is very unlikely to have contaminated any staff who treated Mr Litvinenko or anyone who came in contact with him because they would have had to ingest or breathe in the contaminated fluids from his body.”
An inquest into Mr Litvinenko's death was opened this week at St Pancras Coroner's Court and was adjourned.
The HPA is asking anyone who was in the Itsu sushi restaurant or the Pine Bar or the restaurant of the Millennium Hotel on 1 November to contact NHS Direct on 0845 4647 for advice.