Why has the London election, which seemed a few weeks ago to be on the point of capturing the public imagination, degenerated into a dull Punch and Judy show that even London's local papers can scarcely bring themselves to report?

The lack of interest can be partly put down to the cynicism of the media, whose coverage has revolved almost entirely around the personalities of the candidates and their gaffes - or for the most part, the absence of notable gaffes, which has been a bitter disappointment from the point of view of journalists. This bias has, of course, been justified by the larger-than-life and buffoonish character of the main candidates. As a result, the dinner-party consensus among the chattering classes has turned this election into a question over whether Ken Livingstone or Boris Johnson is the less likely to self-destruct.

Yet this conventional wisdom is completely wrong. Mr Johnson and Mr Livingstone, far from being blundering political innocents, are both politicians of the first rank. Mr Livingstone not only managed to outmanoeuvre and humiliate both Tony Blair and Gordon Brown by becoming the first Mayor of London, but proved himself to be the only British politician of his generation to confront Margaret Thatcher and win in the long run. Mr Johnson cannot, yet, claim any such electoral triumphs, but he has managed to survive verbal gaffes and personal scandals as serious as the ones that ended the career of David Blunkett and a host of Tory Cabinet ministers from the Thatcher years.

Perhaps, then, the farcical character of the London election reflects the lack of interest among voters in local issues. Is it that Londoners do not really care about the policies that fall within the mayor's purview: transport and congestion; crime and policing; pollution, housing and urban planning? To ask this question is to answer it. The list of the mayor's main responsibilities reads like a transcript of almost any bar-room conversation in London. It is, in fact, almost identical to the issues that voters say they are most concerned with when opinion pollsters ask them.

What, then, is the problem with London politics? And what are the chances that either of the two main mayoral candidates will manage to overcome it and emerge, despite the catcalls from the media, as a serious political figure in two weeks' time?

It seems to me there are two main reasons why Britain refuses to take this election seriously, and they have little to do with the personalities involved. The first is the generalised disdain for local politics in Britain's uniquely overcentralised system of government. Because local government is constitutionally nothing more than an agency of Westminster and Whitehall, British politicians with national ambitions are naturally contemptuous of local politics.

Instead of being treated as co-equal with national politics, or at least as a natural pathway to national power, as it is in America, France, Germany and most other democratic countries, involvement in local politics is treated by the British Establishment as either a pitiful consolation prize or, in the case of London, which cannot be denied some status, as a practical joke.

The second reason for the low esteem towards the office of London mayor is related to this overcentralisation, but ought to be easier for the candidates in this election to overcome. This second problem is the power of vested interests and pressure groups that take advantage of the lack of public interest in local government to pursue their single-issue objectives and to subvert or paralyse the few powers that local councils do possess.

To see what I mean, consider just one example of the sort of issues that should have dominated the London election, but which have scarcely surfaced above the nonsensical hubbub about gaffes and jokes.

Starting with transport, both main candidates have criticised the dysfunctional Public Private Partnership that runs London Transport and opposed plans for a third runway at Heathrow airport. But because both of the schemes are being imposed on London through the explicit personal direction of Gordon Brown - and continue to enjoy his direct personal backing - Mr Livingstone can have no credibility on these issues.

Mr Johnson, on the other hand, could be making a big theme of his opposition to Labour transport policies, and especially to the unpopular expansion of Heathrow. David Cameron could offer Mr Johnson invaluable support in this campaign by making an explicit promise to abandon the expansion of Heathrow and to reconsider the management of London Transport if the Conservatives come to national power. Such explicit promises on airport expansion and transport management would be popular with the voters of London and Labour would, by definition, be unable to match them.

Anyone who lives in London and considers politics for just a few minutes a day could think of a host of other ways by which local life could be improved through a new partnership between local and national government. These range from tightening the laws on knife possession and extending the responsibilities of traffic wardens to act as eyes and ears for the police on the streets of London to such elementary, and almost cost-free, improvements as the creation of cycle routes across the Royal Parks. Other improvements could be the erection of sound-baffles on the Westway and elevated sections of the M4 and M11 motorways running through some of the most densely populated areas of London, or the introduction of lane rentals, which would allow local authorities to charge utility companies for the congestion they cause by digging up the streets of London.

Such policies have never been seriously considered because of the vested interests - ranging from the police union to the utility companies - that have deflected public attention from them or successfully opposed them, in the case of lane rentals, even after the necessary legislation has been passed by Parliament five years ago.

The Tories now have a perfect opportunity to cure this paralysing disconnection between local and national government in Britain by taking the London election seriously and getting their candidate elected by committing themselves in advance to national decisions such as abandonment of Heathrow expansion or changes in the policing of London's streets. In doing this, the Tories would put themselves on the path to national power and create a suitable platform for Boris Johnson, one of their most able and charismatic politicians, to show what his party could achieve.

The only shame would be that another of Britain's most able politicians, Ken Livingstone, would be defeated in the process. But then, if the Tory plan were fully successful, there would soon be another job for the outgoing Mayor of London to aspire to. How about the leadership of the Labour Party for Ken after Gordon Brown's defeat in the general election - which would surely follow a victory for Boris in London?

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