British police were searching premises in London today after a Nigerian man tried to ignite an explosive device on a flight from Amsterdam to Detroit.

Prime Minister Gordon Brown said Britain had been working closely with US authorities and investigating the incident since it had happened.

"Because of the serious potential threat posed by the incident, I have spoken to the Commissioner of the Metropolitcan police, whose offices have been carrying out searches of properties in London," Brown said in a statement.

The man was believed to have spent time in Britain as a student and authorities were working to establish the details about his activities in the country, a British counter-terrorism source said.