Britain told American intelligence agents more than a year ago that the Detroit bomber had links to extremists, Downing Street has announced. Umar Farouk Abdulmutallab was named in a file of people based in Britain who had made contact with radical Muslim preachers. The file was sent to the US authorities in 2008. The disclosure will embarrass President Barack Obama, who is already under pressure after failures by US intelligence to identify the bomber. It will also add to concern over the state of the “special relationship” between Downing Street and the White House following last year’s dispute over the...