Whatever you do - don't renege on the Routemaster

What a silly reason, the Roundheads among us will say. But the Routemaster has always been far more than a bus, and with any luck tomorrow's launch will be about far more than transport.

What the Routemaster symbolised was public-service idealism: a conviction made flesh, or at least aluminium, that something in the public realm should be the best thing possible, painstakingly and precisely crafted for the job it did, its future users consulted every step of the way, and an object to grace the city it served.

What the successors to the Routemaster symbolise is the disastrous breakdown in relations between the people who run our public services and the people who use them. Could anything be more contemptuous of its customers than a modern bus? The seats are hard, there are far fewer downstairs than on the Routemaster, and some face backwards. The air is filled with high-pitched beeping noises.

Ventilation barely exists. The buses throw passengers around when they brake. The upper decks are vandalised, filthy and disorderly in a way a conductor-operated vehicle never was. Slow, lumbering, the buses are comically unsuited to London's streets. Their fuel consumption is 30 per cent more than the Routemaster's. Their engines are often ridiculously noisy. And that's before you even get to the bendy bus - which, not content with screwing the passenger and the environment, makes life hell for every other road user too.

No actual bus passenger would have chosen these vehicles, but they weren't designed for passengers. They were designed to comply with often irrelevant regulations and to appease minority pressure groups, such as the disabled lobby, which didn't even speak for the minorities they purported to represent (disability is not confined to wheelchair use; opinion polls showed that most people with disabilities preferred the Routemaster).

The other thing new buses are designed to do is look snazzy and modern. Never underestimate our masters' obsession with outward form, as opposed to function and content. Think, for instance, of the city academies - where the priority has been new buildings, rather than good teachers.

So tomorrow should be not just about delivering a new Routemaster but delivering cultural change in the public services - something of great relevance to that central question in British politics, the one that goes "How can Labour have spent so much on the public sector, yet seen such modest increases in public satisfaction?"

I'm only cautiously hopeful, though. The fact is that TfL is proud of its buses, and despises the Routemaster. Despite all evidence to the contrary, the "transport professionals" think they're doing a great job. The main qualification needed for a career in British public transport is the belief that innovation is too difficult and the glass is half empty. The letters pages of the industry press are full of bus managers scoffing at the public's "sentimental" attachment to the Routemaster and saying a new version will be technically impossible.

Ken, too, came to office as a friend of the RM. But the "transport professionals", above all TfL's head, Peter Hendy, turned him around. Only 10 months ago, Hendy was writing emails discussing how to "refute Boris's transport idea [that] Routemasters are good". Hendy is now making nice noises, for tactical reasons, over the 21st-century Routemaster; but sources say David Brown, TfL's bus boss, is determined that it will not happen until the 22nd century, at the earliest.

Boris's own transport adviser, Kulveer Ranger - another transport pro - has sounded doubtful, too. Even the Mayor himself is muttering about the difficulties, in what sounded like a TfL brief, about the difficulties of replacing the bendies with a vehicle that can carry as many passengers.

Yet experts are often wrong, and they're wrong about this. The Routemaster will cost, but much less than some of TfL's other follies. The industry has an incentive to deliver - London is nearly half the UK market for new buses - and are they really saying they haven't got the technology in 2008 to build something they managed in 1956 ? It won't be hard to match the capacity provided by the bendies, particularly since so many of their passengers are fare-dodgers. Theoretically, a bendy does carry about twice the old RM's load, but all the extra people, and more besides, have to stand. The new RM will be larger than the old one, and will let you sit down. And what TfL tended to do when a route went from Routemasters to bendies was to reduce the frequency - so it should be easy enough to increase the frequency right back again.

It will clearly take several years for the new Routemaster to make its way through design, prototype and production. But what Londoners want to hear tomorrow is that the bendies will go sooner, with an interim double-deck solution in place. Two short bendy routes, the 507 and 521, have already had their contracts extended. The contracts for other, more important bendy routes are up for renewal soon.

In making those, and subsequent decisions about buses, Boris should never forget that he was elected as the people's representative in the bureaucratic machine, the populist among the Roundheads. And the people want the new Routemaster. It's his only specific manifesto item that most Londoners remember. Boris needs to maintain his bus's forward motion not just tomorrow, but throughout all the years of TfL obstruction that will surely follow.

And even if you don't think a bus is important, even if you don't buy my argument about the public services, the Routemaster is a big red test of whether Boris can achieve something still more vital to his Mayoralty: the ability to progress his agenda, and avoid capture by officialdom.