Janet Street-Porter: These cities of the future are just ego-trips

New roads and piazzas don't add character and multi-layered experiences for city dwellers

I'm planning a trip to the nearest cinema to see the latest version of War of the Worlds. There's something utterly captivating about a fully realised fantasy world, even if it stars Tom Cruise and has mixed reviews. As a child, I adored HG Wells, then Arthur C Clarke. Before I'd enrolled to study architecture, I would collect comic books with drawings of gleaming cities inhabited by people with pointy ears or huge domed foreheads.

Futurism is so seductive, so exciting, isn't it? In 1965, the Archigram group created the "walking city", complete with outdoor moving escalators and thousands of living pods for its lucky inhabitants, which they published in an entertaining pamphlet, now a collector's item. If you want to see the work of another visionary, pop along to the Design Museum for the Cedric Price exhibition. A brilliant thinker and theorist, he hardly built anything during his lifetime.

It's important to remember, however, that when writers and film-makers from Stanley Kubrick to Ridley Scott proposed visions of the future to entertain us, they didn't actually expect for one moment anyone would ever take them seriously as blueprints for future living.

But in the Deputy Prime Minister and London mayor, it seems as if we have two would-be futurists; they're so full of their own self-importance, they constantly search for ways to build monuments to their own towering egos. Incidentally, if Ken was a building, he'd be Wembley Stadium - over-designed and over budget, aggressive and hard to ignore.

Instead of adopting the mantra "small is beautiful", both men are convinced that the only way to solve Britain's housing crisis is by building on a vast scale. Prescott is busy pulling down perfectly serviceable terraced housing in Liverpool, because it doesn't fit in with his "master plan". He wants to develop the whole region of the Thames Gateway, a bleak, featureless industrial landscape, a vast undertaking which will require a new transport system, and entirely new support system for the inhabitants, from roads to hospitals to schools.

I'm all for clearing up the Thames Gateway of industrial detritus and turning it into a huge and wonderful leisure park, with plenty of marshland left untouched for wildlife, cleaned-up water for sailing, windsurfing and swimming. People need space like this in the South-east, not an extension of Bluewater or endless estates of little brick boxes.

But if Mr Prescott's proposals weren't worrying enough, now Mr Livingstone has plenty of thoughts about how to turn the east side of London into the new metropolis. He wants to "swing the axis of prosperity from west to east" and build at a high density far closer to the city than the Thames Gateway.

You can start laughing now at the sheer crassness of that remark, as if the high house prices and general desirability of leafy inner city areas like Chiswick, Putney, Richmond and Barnes could easily be replicated by a magic formula in Grays Thurrock and Canning Town. If the west of London has Heathrow, the M3, M4 and M40 threading through it with all the concomitant noise and pollution, it also has street after street of inviting brick housing, parks, open spaces, Kew Gardens and Richmond Park, as well as decent transport and good schools.

But Ken's ideas are gaining support in influential quarters. Last week, the London Development Agency's International Design Committee unveiled their big new idea called City East. This utopian dream involves creating a city the size of Leeds between City Airport and the western end of the Thames Gateway.

Lord Rogers, the Mayor's architectural adviser, talked of high densities and eulogised about the success of Canary Wharf. But, just like the Archigram Group and their wacky proposals 40 years ago, Lord Rogers seems to forget one very important fact - you cannot create a city from scratch.

Canary Wharf is a hermetically sealed environment full of high-earning white-collar workers, containing a wide range of public art showcased in a series of windy, unpleasant open spaces that might have looked great on the drawing board, but only work in the British weather about one day a week. Canary Wharf, with its featureless mall, works as a great place to arrive at and leave.

Around Canary Wharf, life goes on as before, with areas of derelict buildings, rundown shopping centres, litter-strewn ragged patches of grass, and kids hanging around on corners because there aren't enough places to go and let off steam.

Lord Rogers' committee includes some distinguished senior architects including Will Alsop and Sir Terry Farrell, as well as the man responsible for my new house with its leaking roof, David Adjaye. At the centre of it, I fully understand Lord Rogers' passionate desire to develop east London around the river - having walked a huge amount of the Thames Path, there is nothing more infuriating than all the places where the route has been diverted because private landlords don't want the general public walking through their prime piece of real estate with its expensive riverside views.

Most importantly, the whole area is lacking in coherent public transport - and City Airport, although enjoyably uncrowded, is a nightmare to reach by road. The Docklands Light Railway will hardly represent a speedy option even when the extension is completed. But, the biggest reason why City East won't ever work other than as a computer-generated utopia, is that this part of London lacks a heart - and just coming up with a big zappy concept isn't going to change that one iota.

New roads and piazzas don't add character and multi-layered experiences for city dwellers. The grand scheme will have to be funded by private developers - and that will hardly bring in small businesses or offer low rents. It will simply ensure more of the bland chains we have in every town centre all over the country, where any individuality is being forced off the high street.

Around Whitechapel, centuries of immigrants have been absorbed because the streets conform to a human scale, there are still corner shops, grocers and cafés. You can see wonderfully inspirational churches - even if they are underused - and, most important of all, work and living spaces crammed right up against each other. There is noise, colour, a cacophony of building styles, good and mediocre, of every period from the 17th century to the present day.

I have no problem with the concept of high density; after all most people within the M25 can't afford more than half a house anyway - that's how we already live. But don't try and tell us that City East is more than a huge ego-trip for all concerned.