Secret documents reveal that the three Qatari men conducted surveillance on the targets, provided “support” to the plotters and had tickets for a flight to Washington on the eve of the atrocities.

The suspected terrorists flew from London to New York on a British Airways flight three weeks before the attacks.

They allegedly carried out surveillance at the World Trade Centre, the White House and in Virginia, the US state where the Pentagon and CIA headquarters are located.

Ten days later they flew to Los Angeles, where they stationed themselves in a hotel near the airport which the FBI has now established was paid for by a “convicted terrorist”, who also paid for their airline tickets....