LONDON - Britain's top police officer resisted growing pressure to resign on Thursday after he was criticised in a report on the shooting by London police of a Brazilian man who was mistaken for a suicide bomber.

Police shot Jean Charles de Menezes, a 27-year-old electrician, repeatedly in the head on July 22, 2005. They believed he was one of four men who had tried to carry out suicide bombings on London's transport system the day before.

The Independent Police Complaints Commission (IPCC) criticised Ian Blair, commissioner of London's Metropolitan Police, for initially trying to block its inquiry into the case.

Blair has said he believed at the time that the probe would interfere with anti-terrorism cases.

"I intend to remain in this post," said Blair. "By the very nature of its task, the history of the Metropolitan Police Service is littered with controversial events."

The botched attacks came exactly two weeks after four Islamists killed 52 people in suicide bombings on London's transport network.

Last week Blair's force was found guilty of failing to protect the public over the shooting, in an unprecedented criminal trial under workplace health and safety laws.

No individual officers have been punished.

Prime Minister Gordon Brown's government has backed Blair to stay on but the two main opposition parties have called for him to go.

"The Commissioner attempted to prevent us carrying out an investigation," said IPCC chairman Nick Hardwick. "In my view, much of the avoidable difficulty ... arose from this delay in referral."

The officer whose actions drew the greatest scrutiny in the IPCC's report was Cressida Dick, who was in overall charge of the operation. She faces possible public disciplinary hearings along with three other senior officers.

"Very serious mistakes were made that could and should have been avoided," Hardwick said. "But we have to take the utmost care before singling out any individual for blame.

"Those with strong views would do well to study the evidence with the care the jury did" in the health and safety court case.

Blair has said he hopes the IPCC's account will draw a line under the matter. However, a forthcoming inquest into the death of de Menezes and planned civil lawsuits by his family makes this unlikely.

"Although we welcome this report, we sadly are no closer to getting justice," de Menezes's cousin, Vivian Figueiredo, told a news conference. She repeated calls for Blair to resign.