Litvinenko death "unprecedented event in the UK"

Dr Pat Troop, chief executive of the Health Protection Agency, has said Mr Litvinenko's death was an "unprecedented event in the UK" and that he had "apparently been poisoned by a type of radiation".

A large quantity of alpha radiation - probably from a substance called polonium 210 - was detected in Mr Litvinenko's urine, Roger Cox, director of the HPA's centre for radiation, chemicals and environmental hazards, said.