Scotland Yard's announcement of an urgent review of the Damian Green affair is the first step towards dropping an investigation that has embroiled it in an almighty scandal and threatens to wreck the careers of two of its most senior officers.

While the Metropolitan Police has maintained that the inquiry into Home Office leaks is ongoing, the reality is that it has been stalled by the furore. The next logical step for detectives following the evidence would be to interview David Davis, the former Shadow Home Secretary. But the political atmosphere is so volatile that taking that step is now unthinkable.

Many senior police officers were surprised by the decision - taken by Sir Paul Stephenson, the Acting Commissioner, and Bob Quick, the head of special operations - to arrest a frontbench MP as part of an inquiry into leaks to the press.

One said: "It's a massive cock-up, almost incomprehensible." Another added: "This is not about state secrets, it's about politically embarrassing information, why are we involved at all?"

Publicly the police have closed ranks. Behind the scenes, however, there is anger and disappointment that Sir Paul and Mr Quick did not consult more widely with senior colleagues in the police service before embarking on such a high-stakes operation.

Both men are among the applicants for job of Metropolitan Police Commissioner, but the odds of them being successful have lengthened considerably in the past few days. In their first major test in control at the top of the Yard, they have created a much worse mess than anything Sir Ian Blair managed in his "gaffe-prone" four years as Commissioner.

Sir Paul has asked for an interim report in a week's time and a full report in 14 days. Barring another moment of madness at the Met, some sort of explanation will have been cobbled together by then for dropping this unnecessary and calamitous investigation. The issue then will become whether or not Sir Paul and Mr Quick stay in the race to become Commissioner.

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