Onwards and Upwards

Tall buildings beamed into the living-room on television and framed in a 21-inch screen still have the power to make the palms sweat. It is their sheer size in relation to what is happening around them - the way workers on the Millennium Dome at Greenwich look like ants when the camera pans 850 feet down from Canary Wharf, or the unsettling way the Thames appears to ripple up Millbank Tower's curved curtain wall. So when the boyish new director of the Museum of London, Dr Simon Thurley, does a piece to camera on BBC 2's One Foot in the Past heritage series from the window cleaners' platform suspended 600ft outside the International Financial Centre, you feel the fear of the bungee jumper.

But as its cameras zoom vertiginously up into London's skyline on 27 August, One Foot in the Past points two fingers at the heritage lobby and takes a giant step for mankind in championing the rejected Millennium Tower, designed by Foster Associates. At 1,427ft, it would have been the tallest building in Europe, twice the height of its City neighbour, the International Financial Centre (formerly the NatWest tower) at 600ft, and twice its bulk.

But it may be too late. If the client, Alan Winter, chairman of London Millennium Tower Ltd, has to build a redesigned pygmy version, which he saw for the first time two days ago, he will pre-let it for commercial reasons to a single financial institution and let the tenants name it. So the not-so-towering Millennium Tower could be, say, the Deutsche Bank building.

Cities always compete architecturally with each other and it is always over height. For a heady moment, London had something planned on the Manhattan scale. But not for long. English Heritage and the City of London Corporation explained that Norman Foster's original tower was "a step too far". So the architects were asked by their client to come up with some new ideas.

Plan A was to lop off a third of the tower without changing its design. Nobody liked this castrated version, least of all the architect. Now Mr Winter has to guess, with his board, which of the two other versions is most likely to get planning permission and be commercially viable.

The tall, slim one can still justifiably be called the Millennium Tower. This supermodel stands at just under a thousand feet tall, a little taller than Canary Wharf. The short, fat one, which Mr Winter admits is "not as stonkingly big and beautiful but still recognisable as a Foster design with its curved glass front", is only 380ft, and still doesn't have a name. The version they choose will be shown to English Heritage and the City of London Corporation before being submitted for planning permission later this year.

One of the things that everybody liked about the Millennium Tower was that it wouldn't shut down at night. Restaurants, health club, public viewing platforms, shops, people living there would keep it buzzing. Mr Winter says, "We believed that at a scale of about 1.6m sq ft, with something like eight to ten thousand people working in the building, mixed usage was justifiable in commercial terms. But in the smallest version, which will be pre-let to a major financial institution, there will be none."

The feasibility of mixed use within the 1,000ft tower is still being looked at. If it is built, it will be a speculative building for a large number of smaller lets.

Ultimately, the design has been driven by English Heritage, the Government's official adviser on conservation, and the City Corporation. In the bad old Bottomley days, English Heritage proposed that no building should be taller than a hundred metres (about 320ft), just two laps of an Olympic- sized pool. When at the end of May English Heritage staged a symposium called Planning Change in a World City, for movers and shakers to voice their opinions on tall buildings, bridges and better architecture, Jocelyn Stevens, chairman, said: "We believe that good design should have nothing to fear from informed opinion and constructive dialogue" So he knows that the consensus on towers was that they are good things in the right place, preferably in clusters, and that they should have mixed use. Otherwise, the revisionists will have everyone working out of Henley or Croydon.

Maybe the flat-earthers will be won over by Simon Thurley on the BBC series. He argues that it is in the right place for new sculptural high rises, alongside NatWest tower and the modestly sized 12-storeyed Lloyd's building. Even Sir Christopher Wren would have approved the city plan, he assures us.

Thurley also who wants it on the record that our ancestors would have admired the Millennium Tower rather than opposed it. Londoners in the Middle Ages were just as eager to build tall - not only 121 churches to reach the sky, but the medieval St Paul's cathedral, which stood at 468ft high before the Great Fire destroyed it. Wren's original design for the new St Paul's was topped by a 400ft spire. The one he eventually built stands at 365ft.

Every generation has built to overwhelm the last. A tower on the roof of Selfridges, designed in 1918 by Philip Tilden, would have brought it to an astonishing 560ft, while the Imperial Monumental Halls and Tower, designed in 1904 by John Pollard Seddon and Edward Beckitt Lamb to fit between the Houses of Parliament and Westminster Abbey, was 500ft. But building heights were restricted to the reach of a fireman's ladder. While Chicago and New York took off, London continued to underwhelm its visitors.

One genuine example of a transatlantic skyscraper was sleuthed by the BBC team. Next door to the Ritz, Devonshire House, built in 1928 by a New York firm, Carrera & Hastings, is a template for skyscrapers with its fancy top, repetitive middle and grandiose street elevation. But it is only nine storeys high.

When modern planning laws were first applied to tall buildings in the UK it was the 1960s, a time of greedy developers striking deals and multinationals imposing conditions - the Hilton wouldn't open in London unless it built big.

The Nineties version of piecemeal planning is design by committee - an approach that never works. Foster's Millennium Tower - too tall, lop off a bit here, add a bit on there, redefine the use - has provided a chastening example. Whatever happens, it will be watered down from his original shining vision for the 21st century.