Can Scotland Yard chief win his battle for survival?

Only 17 months after he arrived at New Scotland Yard on a mission to transform Britain's largest police force, the world is closing in on Sir Ian Blair. He is losing the support of rank and file officers, has senior colleagues briefing against him and has allowed relations with the police watchdog to fall into deep freeze.

He faces vitriolic opposition from some of the country's most powerful newspapers and the Metropolitan Police Authority - which has the power to force him from office - is said to be split on whether he should survive.

Public declarations of support from Downing Street and the Home Office are not matched by the private doubts of senior Ministers over whether the Commissioner can survive the firestorm. Even David Cameron, the Tory leader, yesterday sidestepped questions on whether Sir Ian should step down.

Sir Ian has told friends he has no intention of resigning and believes he retains the confidence and support of Tony Blair and John Reid, the Home Secretary. But allies accept his political support is not limitless and believe it is inevitable he will face demands for his resignation when the inquiry into the shooting of Jean Charles de Menezes is published.

How did Sir Ian's fortunes collapse so spectacularly and so fast? Supporters point to the hostility of right-wing newspapers, led by the Daily Mail, who aresuspicious of the Commissioner because of his perceived closeness to the Prime Minister.

Sections of the Police Federation, which represents beat officers, were antagonistic from the day he took over. Sir Ian blames the hostility on their resistance to his plans to boost the role of community support officers, while his critics insist it is caused by his failure to relate to the Met's footsoldiers.

Equally damagingly for Sir Ian, substantial numbers of senior officers want him to quit. According to one recent estimate, 140 of his Superintendents, Chief Superintendents, Commanders and Deputy Assistant Commissioners now think he should be replaced.

From the moment he tried to delay an investigation by the Independent Police Complaints Commission (IPCC) into the accidental shooting of Mr Menezes, the Commissioner has also been at loggerheads with the police watchdog. It did not help matters that it emerged later he had secretly taped telephone conversations with IPCC investigators.

Meanwhile, support for Sir Ian appears to be ebbing in the police authority, little more than a year after he warned its members not to hire him if they did not want a reforming Commissioner.

His allies are heartened by the fulsome support of the Mayor of London, Ken Livingstone, who has claimed Sir Ian is the victim of a witch-hunt by right-wing newspapers.

Although they also insist he retains the confidence of the Home Office and the majority of police authority members, there is a sense of the growing embattlement in Scotland Yard. For all the complaints about the unfair treatment Sir Ian is receiving, there is little disguising the fact that he authored much of his downfall.

His insistence, five hours after Mr Menezes's death, that the shooting was "directly linked to terrorist operations" was embarrassing as some colleagues already suspected that the Brazilian was innocent.

He naively failed to foresee the controversy over his comment that he could not understand why the murders of Soham schoolgirls Holly Wells and Jessica Chapman in 2002 "became the biggest story in Britain".

The disclosure he had covertly recorded conversations with Lord Goldsmith, the Attorney General, as well as IPCC members, was a disastrous own goal.

The final blow could come within weeks with the publication of the IPCC inquiry, which contains a devastating critique of Scotland Yard's performance under his stewardship.

The man who may bring him down

The acrimony between Scotland Yard and the Independent Police Complaints Commission (IPCC) pits old foes against each other. The two most senior posts in the police watchdog are held by former human rights activists - its chairman Nick Hardwick, 48, was the for eight years the energetic chief executive of the Refugee Council. His deputy, John Wadham, previously headed the civil rights group Liberty from 1998, and acted as a lawyer to former MI5 agent David Shayler.

Sir Ian Blair, the Metropolitan Police Commissioner, also has liberal instincts - which led to led to gibes within his force that he believed PC stands for "political correctness". But any initial goodwill between Sir Ian and the IPCC vanished on July 22, when they clashed over whether there should be an independent investigation into the killing of Jean Charles de Menezes. The IPCC chairman gave as good as he got and relations between the two men are said to be beyond repair.

Mr Hardwick, 48, was appointed the first chairman of the IPCC four years ago. His message to chief constables at the time was: "If you do the job right, we won't be on your backs so much."