The political establishment swung behind Sir Ian Blair, the Metropolitan Police chief, last night after his force was found guilty of serious failures which led to the death of innocent Brazilian Jean Charles de Menezes.

Sir Ian Blair resisted calls to resign despite claims that his position had now become "untenable".

The force was fined £175,000 and ordered to pay £385,000 costs after being convicted by an Old Bailey jury of exposing the public to risk.

After the verdict Prime Minister Gordon Brown, Jacqui Smith, the Home Secretary, and London Mayor Ken Livingstone insisted they fully supported Britain's top police officer.

Expressing sympathy to the dead man's family, Ms Smith said the UK Government would consider the implications of the verdict, adding: "The commissioner and the Metropolitan Police remain in the forefront of the fight against crime and terrorism. They have my full confidence and our thanks and support in the difficult job they do."

However, David Davis, her Conservative shadow, said Sir Ian's position was "untenable in light of these findings and the overriding need to restore public confidence".

The £3.5m trial heard how a "catastrophic" series of 19 key failures in police procedure led to Mr de Menezes, 27, being shot seven times by armed police officers at Stockwell Underground station.

He was followed from a block of flats in Tulse Hill, south London, linked to the failed July 21 suicide bomber Hussain Osman. An undercover police officer, meant to identify the suspect, was unable to do so as he was "relieving himself" at the time.

The court heard that a surveillance operation at the flats was ordered at 4.55am but firearms officers had still not arrived four hours later.

Mr Justice Henriques, said this delay was one of the key failings by the police. It meant Mr de Menezes was not stopped before boarding a bus and Tube passengers were potentially exposed to a suicide bomb attack. It also led to Mr de Menezes's death.

He also singled out the apparent communications breakdown in the Scotland Yard control room, headed up by Commander Cressida Dick, which may have been caused by a noisy atmosphere there.

"There was a serious failure of accurate communication which has simply not been explained," said the judge.

Mr Henriques backed comments by the jury, which in a rare move added a rider to its verdict to say "no personal culpability" should be attached to Ms Dick, who had been fed "inaccurate information".

Ms Dick, who has since been promoted to deputy assistant commissioner, is one of four senior officers still facing disciplinary charges over the shooting.

The judge said: "I am deliberately not going to name any individual as having failed. This was a corporate failing with a number of failures contributing to the tragedy."

Sir Ian, who was in court to hear the verdict, expressed his "deep regret" for the "tragedy".

He said: "This case provides no evidence of systematic failure by the Metropolitan Police." Declaring he would not resign, he added: "I am going back to New Scotland Yard to get on with my job."

Last night, the dead man's relatives said. "We remain determined to ensure the full truth about Jean's death is made public and those responsible are held accountable in a court of law," said cousin Erionaldo da Silva.

Harriet Wistrich, the family lawyer, claimed the tactics of the defence team "descended to the gutter, seeking to shift the blame on to the victim".

In court, Ronald Thwaites, for the police, had claimed Mr de Menezes was acting in an "aggressive and threatening manner" when he was killed. The QC was also criticised by the family for his "cynical" use of a composite photo of Mr de Menezes and Osman to try to show how difficult it would have been for police to distinguish between them.

Following the court verdict, the Independent Police Complaints Commission said it now hoped to publish its report into the fatal shooting "within days".

A full inquest into Mr de Menezes's death is due next spring.

The 19 allegations

  • 1 Failing adequately to communicate Commander McDowall's strategy to the officers who took over running of the operation on July 22.
  • 2 Failing adequately to plan for or carry out his strategy for controlling the premises.
  • 3 A "confused and inconsistent" understanding among the Scotland Yard control room officers and the surveillance officers of what the strategy was for Scotia Road.
  • 4 A failure to deploy officers to stop and question people emerging from the Scotia Road premises.
  • 5 A failure to ensure an SO19 firearms team was there when Mr de Menezes emerged from the communal doorway.
  • 6 A failure to have a contingency plan to deal with people emerging from the flats before SO19 arrived.
  • 7 A failure to stop and question people emerging from the flats.
  • 8 A failure to identify a "safe and appropriate" area where those leaving could be stopped and questioned.
  • 9 "Inaccurate and unbalanced" briefings given to firearms officers at Leman Street and Nightingale Lane stations, which gave them "inadequate and inaccurate information" about the operation.
  • 10 Information about the identification of Mr de Menezes, his clothing, demeanour and "likely level of threat" was "not properly or accurately disseminated to officers and in particular the firearms officers".
  • 11 A failure to ensure that doubts about the correctness of the identification of Mr de Menezes as the suspect were communicated to relevant officers in the control room in Scotland Yard.
  • 12 A failure by control room officers to satisfy themselves that a positive identification of Mr de Menezes as the suspect had been made by the surveillance officers.
  • 13 A failure to deploy firearms officers at relevant locations in time to stop Mr de Menezes getting on to the bus and into the Tube station.
  • 14 A failure by firearms officers to satisfy themselves that a positive identification of Mr de Menezes as the suspect had been made by the surveillance officers.
  • 15 A failure to take effective steps to stop Tube trains or buses or take other "travel management steps" to minimise the risk to the travelling public.
  • 16 That Mr de Menezes was allowed twice to get on to a bus and to go into the Tube station despite being a suspected suicide bomber and emerging from an address linked to a suspected suicide bomber.
  • 17 A failure to give a "clear or timely order" that he must be stopped or arrested before entering Stockwell Tube station.
  • 18 A failure to give accurate information to Commander Dick about where specialist SO19 officers were when she was deciding whether they or Special Branch (SO12) officers should stop them.
  • 19 A failure to minimise the risk in arresting Mr de Menezes by armed officers "whether in relation to the location, timing or manner of his arrest".