Staff at a hotel visited by a man suspected of being Britain's sixth victim of Sars have been urged to be aware of the symptoms of the deadly virus.
The latest possible victim, currently in isolation at London's Northwick Park Hospital, held a meeting at the Marriott Heathrow Hotel with a Hong Kong businessman who has now being treated for Sars in his own country.
The pair met for the one-to-one talks on April 3 and the visitor from Hong Kong, who had stayed at the hotel the previous night, left for Germany later that day.
The Health Protection Agency says it had begun an investigation into the circumstances of the stay at the Marriott on a "precautionary basis".
In a statement, the HPA said: "As a precautionary measure, members of the Hillingdon Health Protection Team and local Primary Care Trust are now working closely with the Marriott Hotel to provide health advice to management and staff and to obtain further details regarding the guest's stay."
The agency said that based on current World Health Organisation advice, the risk to staff and guests at the hotel on April 2 and 3 April was "extremely low" and there should not be any risk to guests who stayed after those dates.
To date, more than 100 people have died as a result of Sars around the world.
Story filed: 17:12 Saturday 12th April 2003
But for 10% of those infected, their lungs rot to the point that they can't breathe by themselves.