Telegraph: The American al-Qa'eda operative unmasked last week as having planned to bring down the Brooklyn Bridge was first detained in March, and has been used by the FBI for months as a double agent, it was reported yesterday.

US authorities waited until last week to announce a plea bargain struck with Iyman Faris, a Pakistani-born lorry driver ordered to scout out terror targets, including the New York landmark.

They did not say that Faris, who was also ordered to study ultralight aircraft, and the possibility of derailing a train into a chemical storage facility in Washington, had been under FBI control for months.