A senior al Qaeda suspect in Britain, who was reportedly in the final stages of planning an attack on Heathrow, has been arrested by anti-terrorism officers.

His seizure follows a tip-off from Pakistani Intelligence which claims that he was receiving direct orders from Osama bin Laden.

Detailed maps of Heathrow and other information about the airport were reported to have been found on a computer belonging to Mohammed Naeem Noor Khan, whose role was to send coded orders to al Qaeda agents around the world.

A Pakistani official said that Khan has described how he sent scores of encrypted messages to the man he knew as the head of an al Qaeda cell in Britain.

The operative is one of the nine men held in London during armed raids by Anti-Terrorist Branch officers and MI5 on Tuesday. One has since been released without charge.