Britain failed to trace 9/11 plotter

British intelligence failures were implicated for the first time in the September 11 atrocities today after an American investigation claimed that key information on one of the plotters was mishandled in London.

A report by the 9/11 commission says Britain failed to act on a request for intelligence about a French Moroccan arrested only weeks before the attacks.

Zacarias Moussaoui, now on trial for alleged involvement in the plot, is said to have had links to the hijackers through an al Qaeda cell in Hamburg.

He was detained in the US on 16 August 2001 as he learned to fly a jumbo jet. He had lived in London and an FBI attaché ©s said to have hand-delivered an urgent request for information on him to the British Government.

It is claimed intelligence agents here took until 13 September to tell the Americans Moussaoui had attended al Qaeda training camps in Afghanistan.

The US criticism will infuriate MI6 and MI5 and will embarrass Tony Blair ahead of his Washington summit with George Bush. A Foreign Office spokeswoman today rejected the claims, saying: "The British Government had no information that could have prevented the 9/11 attacks."