Italian Mario Scaramella, a contact of dead ex-spy Alexander Litvinenko, has tested positive for polonium-210. Mr Scaramella is not thought to be suffering symptoms but significant amounts of the substance are understood to have been found in the academic. He met Mr Litvinenko at sushi restaurant Itsu in central London on the day he fell ill.
Meanwhile it turns out that both Tessa Jowell and Seb Coe travelled on one of the 'contaminated' planes.
British Airways is contacting 33,000 passengers from 221 flights, but the airline and the government have stressed any risk to public health low. It is referring concerned passengers to NHS Direct. An NHS Direct spokeswoman said only passengers who feel unwell should call. A total of 217 people have been seen by a specialist assessment clinic.
The FBI is now involved.
British Airways has set up a special helpline for customers in the UK on 0845 6040171 or +44 191 211 3690 for international calls. Passengers who travelled on those flights and want further advice are advised to telephone NHS Direct on 0845 4647.