Unanswered questions continue to mount for beleaguered Met chief

Hours after the shooting, the Commissioner said: "As I understand the situation, the man was challenged and refused to obey police instructions."

Statements from police officers involved in the shooting incident, contained in leaked documents, have disclosed that one officer had pinned the Brazilian down on to a seat on the Tube while surrounded by at least two other surveillance officers. It was at that point, according to the witness statement, that he was shot eight times, by members of a four-strong firearms unit. The suggestions that he was properly challenged and had refused to obey do not tally with the statement.

Sir Ian later gave an even more detailed statement that read: "The man who was shot was under police observation because he had emerged from a house which was under observation because it was linked to the investigations. He was followed by surveillance officers to the station. His clothing and behaviour added to officers' suspicions."

This now appears at odds with the disclosure that Mr de Menezes was wearing a light denim jacket and was innocent so had no reason to be acting "suspiciously".

The question remains as to who provided the source material and then briefed the Commissioner with the apparently false information - no one has suggested that he deliberately put out a false account - and why did no one correct it when fuller details emerged?

Lawyers for the dead man's family have argued that it suited the police for the media to portray the electrician in a negative way.

Witnesses to the shooting told reporters Mr de Menezes had leapt over the ticket barriers, that he had wires sticking out of a belt, and had run into the Tube train where he tripped and was shot. All these accounts now appear to be inaccurate. Witnesses are notoriously unreliable, which is why it is crucial to get their observations collaborated with other evidence such as CCTV. Unfortunately only one camera appears to have been working. It may be because police had removed the camera hard drives the day before in the afthermath of the attempted bombings.

Sir Ian insisted there had been no attempt to "cover-up" the details of the shooting. His defence follows criticism of his attempts in the immediate aftermath of the shooting to write to the Home Office and ask for the inquiry to be held as an internal police matter rather than by the Independent Police Complaints Commission.