Give the Mayor the power to fight crime in our city

So who will deal with it? Boris Johnson's high-profile encouragement for the police to use knife scanners certainly can't hurt - but unless it is backed up by a real shift in the accountability of London's police, there is a risk that we will not get the concerted action over time that we need. For the control of policing in London is a mess.

At present, London's response to crime is determined partly by the Metropolitan Police - but just as much by politicians in Westminster. The Government's approach is not targeted at London: instead, it has passed innumerable criminal justice acts, creating dozens of new crimes and stipulating minimum sentences for particular offences.

Their effect in the capital is at best unclear. Meanwhile, there are occasional local crackdowns: in 2003, following a steep rise in the number of muggings in London, the then Home Secretary David Blunkett demanded the Metropolitan Police Commissioner take action to stem the upsurge in street crime.

Yet crime statistics have become virtually impossible to interpret, for London as elsewhere. There are two different sets of figures for England and Wales, which involve different coverage and definitions. "Reported crime" numbers, which have seen regular re-classifications and whose interpretation requires elaborate expertise, show a falling rate overall.

But perceptions of crime show no sign of abating. People simply do not believe the rosy picture painted by the Home Office. Research published by Mori shows crime remains the public's number-one concern and that people in Britain are far less confident in the Government's ability to tackle crime than in other countries. Is it surprising that this should especially be so in London, where despite an elected Mayor, the police's priorities are determined largely with reference to politicians unelected by Londoners?

Even when London elects a Mayor with a strong anti-crime agenda, his power to change the priorities of the police is limited. Boris Johnson successfully targeted Ken Livingstone's record on crime and, in particular, the apparent increase in the number of young people killing each other. He promised more police and "crime mapping" to show where problems are worst. The ban on drink on the Tube and buses is an early step towards clamping down on anti-social behaviour. But his efforts to tackle knife crime involve the Government, the police and the boroughs - and as such, he will be lucky to make much of an impact.

There is surely a powerful argument for sorting out police accountability in London. The existing arrangements locate responsibility for the capital's policing in four different places. The Home Secretary, on behalf of the Queen, appoints the Commissioner. The Mayor sets the Met's budget. The Metropolitan Police Authority (MPA), a minority of whom are appointed by the Mayor, is responsible for "non operational" policy, while the Commissioner takes charge of "operational" policing. Many issues affecting crime and disorder are handled at the local level, where borough councils increasingly have a significant role.

It's more complicated than that, too. There are two other constabularies operating in London: the City of London has its own force, while the Underground and commuter rail system are the responsibility of the British Transport Police. The latter provides some of the capital's most visible policing: for some reason, Londoners are far more likely to see officers underground than in the streets or on buses.

Both the Conservative and Labour parties have now suggested that chief constables might, in future, be elected. But in London, there is a strong argument for giving the Mayor the power to appoint the Metropolitan Police Commissioner. While Boris Johnson and Sir Ian Blair have, it would appear, kissed and made up, it would be an improvement for accountability if in future London's elected first citizen appointed the chief of police. Put the other way round, an elected Commissioner would be a very bad idea.

If the Mayor appointed the Commissioner, other changes ought to follow. The Mayor should also appoint the MPA. The Assembly could then provide scrutiny of policing, in the way it currently oversees Transport for London. More radically, there would be a strong argument for extending the Mayor's capacity to determine the deployment and operations of the police. That is, the Mayor would have a voice in operational policing.

That could also be an impetus to giving borough commanders the power and autonomy they need to make a real difference on their patch, as such a move has done in many US cities. It would fit well with the use of published "crime maps" as proposed last week, again proved to be a useful tool in the US for bearing down on crime in areas where it remains stubbornly high.

Such changes would be controversial in Britain, where chief constables have traditionally been independent. But if the public are to feel they have a direct democratic link to police priorities, the Mayor should be given greater powers over day-to-day policing. We have gone long past the time when people would readily accept authority. Police officers need to be directly backed by the legitimacy of the Mayor's mandate when they use their powers.

In the current climate, the Government and the police need to show that law and order is effective. The public has complex and even contradictory views about policing. It wants officers to be both social workers and "zero tolerance" Robocops. But whatever the approach the public really wants, legitimacy, transparency and local control would give the public more confidence in policing. The existing arrangements palpably do not deliver.

A good mayor would be able to provide both the police and Londoners with a clear, comprehensible policy for policing the capital. London would be able to determine its own approach to its crimefighting needs. And that would surely help us towards a solution to the killings presently disfiguring this city and its young people especially.

Tony Travers is director of the Greater London Group at the London School of Economics.

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