Asked about the theory that the bombers made a mistake, Jubeir said: "That may very well be the case. The compound used to house employees from Boeing Corporation up until about five years ago. These employees hailed from many different countries including Europe and the United States and Arab countries."

"We really want to know the details here," said Lorie Van Auken of New Jersey, whose husband, Kenneth, was killed at the World Trade Center. "I don't understand what's so secret about that. I mean, this is not a game."

There is further embarrassment for the security services. Bugging of or phone taps on foreign embassies, high commissions or any other buildings in Britain requires a warrant from the home secretary, but the Home Office is adamant that David Blunkett did not sign one. If the Home Office is telling the truth, it suggests that MI5 was acting on a freelance basis, reawakening comparisions with the Spycatcher row in which rogue agents tried to destabilise the Wilson government in the 1970s.