Menezes: Cressida Dick and senior officers in the clear

The Independent Police Complaints Commission cleared four senior officers, including Cressida Dick, in charge of the operation, of misconduct. The family of the Brazilian - shot dead after being mistaken for a suicide bomber at Stockwell Tube station in July 2005 - branded the decision a "scandal".

Ms Dick, now a deputy assistant commissioner, and three others codenamed Silver, Trojan 80 and Trojan 84 all faced disciplinary action over their handling of the operation. But a jury in a prosecution brought under health and safety legislation had already ruled Ms Dick could not be blamed personally, and today the IPCC said that made it impossible to discipline the then commander.

It said it was impossible for the other three officers to be blamed personally if their commander could not.

An IPCC spokesman: "The health and safety trial verdict made it clear that mistakes were made that could have been avoided. The issue considered by the IPCC was whether those mistakes amounted to personal misconduct."

The other three officers included a detective chief inspector, known as Silver, and two firearms officers acting as advisers to Ms Dick.

The decision is a major boost for embattled commissioner Sir Ian Blair. Scotland Yard said it was "pleased" by the move as Sir Ian himself said he had never planned to quit. "I'm not thick skinned - I'm just tough," he said.

Asked if the pressure ever made him want to resign, he said: "Quite a way off - I'm a bit of a limpet, really. I did not at any stage consider resigning."

He said the Met had improved under his leadership, with falling crime rates, more officers, lower sickness rates and rising detection levels. "If I believed that my staying was going to damage the service that I have given my working life to, then of course I would go," he said.

"I was appointed to reform the Met and I'm gong to continue to do it."

Today's move means no officer will be prosecuted or disciplined for the shooting of the innocent man who was mistaken for Hussain Osman on the day after the failed 21/7 terror attacks. The

Crown Prosecution Service had ruled out charges after 15 officers were interviewed under caution on suspicion of offences ranging from murder to attempting to pervert the course of justice. The watchdog had cleared 11 of the 15 - all frontline firearms and surveillance officers - of any wrongdoing in May but had waited until the health and safety trial before considering whether to recommend disciplining Ms Dick and her colleagues. Today Mr de Menezes' family called it "the worst Christmas present" they could get and said the Government should review the actions of the IPCC.

His cousin, Vivian Figuierdo said it was "entirely premature" to have made the announcement before an inquest - expected next year. She said: "The decision today is a scandal. Sadly we have come to expect this from the IPCC. They have done nothing to hold the police to account for the killing of an innocent man."

The office of the Commission of the Metropolitan Police was convicted of breaching health and safety legislation over the killing of Mr de Menezes and fined £175,000.