Leading article: Public confidence and a crisis that is too good to waste

A week ago, three senior Metropolitan Police officers – two now retired, one still in his post – appeared before the Commons Home Affairs committee. They had come to defend themselves and the Met over its tardy handling of the phone-hacking accusations. Rather than being heard in deferential silence, however, they found their responses challenged, disbelieved, even laughed at. They were savaged.

Then, this looked about as bad for the police as it was going to get. In the event, though, last week's humiliation turned out to be but the prelude. On Sunday, the Met Commissioner, Sir Paul Stephenson, resigned, with a little encouragement from the Mayor of London, Boris Johnson. Yesterday, Assistant Commissioner John Yates, followed him.

The nemesis of both men was Neil Wallis, a former deputy editor of the News of the World, who had subsequently worked as media consultant for the Met. He was arrested last week in connection with phone hacking. While both officers were personally friendly with Mr Wallis, they have stressed that there was no impropriety. Whether or not there had must be one element to be considered by Lord Justice Leveson. That part of his inquiry, however, waits on two current Met investigations: into phone hacking, and alleged payments to police. Decisions on the future of the Met do not enjoy similar luxury of time.

With one year to go before the Olympics – a security and policing task probably without precedent – the Met is being led temporarily by the Deputy Commissioner, Tim Godwin; an outsider is being brought in as his deputy, and there is a new Assistant Commissioner in charge of counter-terrorism – Cressida Dick, who directed the botched operation that led to the shooting of Jean Charles de Menezes. Two internal investigations, Weeting and Elvedon, are in progress; the Leveson inquiry is in prospect. Overall, this is not a situation to inspire confidence, even if the need to restore public trust was the reason, ultimately, why Sir Paul and Mr Yates both had to go.

For the Metropolitan Police this is a crisis, one of the most severe, if not the most severe, it has ever faced. But to paraphrase President Obama's former chief of staff, it could also be seen as a crisis that is too good to waste. The Home Secretary, who has waged running battles with the police establishment – over cuts, working practices and much else, since she came to office – seized the chance yesterday to change the terms of engagement, announcing a parliamentary review into police corruption. For a British public accustomed to believe in the superiority of their police, this is a juxtaposition many will find shocking. Nor is it a course without risk: the reputation of the police may have to get worse before it can get better.

But this crisis is centred in the Met, where there are two urgent questions to be addressed. The first concerns continuity. It is of paramount importance that the present ructions, as they make their way through the ranks, should not jeopardise the counter-terrorist effort or the Olympics. Yet the dangers should not be exaggerated. Ms Dick's move to counter-terrorism signals continuity, while much of the early Olympic planning, as well as the successful policing of the royal wedding, took place during Sir Paul Stephenson's absence through illness. These are strictly professional, operational issues.

That the Met faces the summary departure of a commissioner for the second time in three years prompts the second question: is the job as it is constituted do-able? While the last two holders may have exhibited frailties, the dual responsibilities of the commissioner – for national policing and for London – look increasingly incompatible and too broad. Even if the Mayor of London and the Home Secretary this time avoided the open clashes that marked the departure of Sir Ian (now Lord) Blair, responsibility for appointing, and ousting, the Met Commissioner uneasily straddles these two jurisdictions.

And it is hard to see how there can be clarity unless the two functions are split. The case for a Metropolitan Police for London, answerable to the Mayor, and a national force to handle counter-terrorism, organised crime and the like, looks ever more persuasive. This is where the Home Secretary should next turn her sights.