Maybe Saddam can shed a little light on this:

Iraq's coalition government claims that it has uncovered documentary proof that Mohammed Atta, the al-Qaeda mastermind of the September 11 attacks against the US, was trained in Baghdad by Abu Nidal, the notorious Palestinian terrorist.

Details of Atta's visit to the Iraqi capital in the summer of 2001, just weeks before he launched the most devastating terrorist attack in US history, are contained in a top secret memo written to Saddam Hussein, the then Iraqi president, by Tahir Jalil Habbush al-Tikriti, the former head of the Iraqi Intelligence Service.

The handwritten memo, a copy of which has been obtained exclusively by the Telegraph, is dated July 1, 2001 and provides a short resume of a three-day "work programme" Atta had undertaken at Abu Nidal's base in Baghdad.

In the memo, Habbush reports that Atta "displayed extraordinary effort" and demonstrated his ability to lead the team that would be "responsible for attacking the targets that we have agreed to destroy".

The second part of the memo, which is headed "Niger Shipment", contains a report about an unspecified shipment - believed to be uranium - that it says has been transported to Iraq via Libya and Syria.

Niger shipment? Wasn't that debunked? Maybe not.