Senhor de Menezes, a Brazilian electrician, died as eight shots were pumped into him in a Northern Line carriage at Stockwell Underground station in South London on July 22 after unfounded suspicions that he was a suicide bomber.

He died under rules set out in Operation Kratos, the national strategy for dealing with suspected suicide bombers. Police commanders can authorise marksmen to stop a suspect they believe is a would-be bomber by shooting him or her in the head.

The Kratos rules require the police commander to issue a code word to the police teams telling them that they should take the ultimate sanction. Scotland Yard sources say that Commander Cressida Dick, 44, the Oxford graduate who was “gold command” of the operation, maintains that she never gave the seven-letter word.

Ms Dick has told colleagues she did tell the officers following Senhor de Menezes that they must “stop him getting on the Tube at all costs”, but nothing more. Police have admitted that there were difficulties keeping in contact with the police teams once they went underground at the station and the two marksmen from the CO19 unit believe that they were authorised to kill Senhor de Menezes.

Investigators from the Independent Police Complaints Commission have been unable to use the radio transmissions to the marksmen to discover exactly what was said because they were not recorded, unlike 999 calls, which are kept.

But the IPCC team should have police logs of the operation that will record all decisions that were taken. They are also investigating the briefings before the operation and the failures in intelligence that put an innocent man in jeopardy. It is not clear if there is one code word used for all Kratos operations or whether it changes each time.

The IPCC will also want to know the basis of the briefings, who gave them, what was said about authorisation and when.

Senior Yard officers are already forecasting that the IPCC inquiry will reveal serious organisational and communications failures, which may raise new questions about the overall responsibility of Sir Ian Blair, the Commissoner of the Metropolitan Police.

Ten officers including Ms Dick have been served with police regulation warnings that they may face disciplinary action. They include the CO19 officers and Special Branch officers involved in the operation.

The IPCC has also identified a group of “significant” witnesses who are being questioned. These are likely to include up to a dozen other officers, including the chain of command between Scotland Yard and the operation in South London.

Leaked witness statements from officers who took part in the operation have disclosed that Senhor de Menezes was restrained before being shot. Documents and photographs from the IPCC investigation also showed that one of the undercover team meant to be identifying the shot man was relieving himself as Senhor de Menezes left his flat and could not tell whether the police had traced one of the alleged bombers.

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