The friendliest brick box in Britain

"If we were to make no special effort and were simply to create a big, brick box full of modern art at Bankside, we could still guarantee to attract between 1.5 million and 2 million visitors a year." Nicholas Serota, newly re-appointed director of the Tate Gallery is under no illusion that art galleries have become a part of the mass leisure and entertainment market.

Art, particularly on a Sunday, draws the crowds as readily as its rivals: shopping, sport, garden centres and getting stuck on the North Circular. If the Tate Gallery is extraordinarily popular - the doors have to be closed during opening hours on many Sunday afternoons to prevent overcrowding - this has as much to do with the fact that it is there (like Mount Everest or the Queen) as it does with the gallery's annual re-hangs, the perennial controversy surrounding the Turner Prize or the dramatic spectacle of exhibitions like the current "Rites of Passage", in which the artist Mona Hatoum takes us on a journey into her interior world via each and every orifice, disgusting some, exciting others and surprising all.

Major city art galleries have become, without doubt, a vital and buzzing junction box on the leisure and tourist circuit, generating considerable income while rivalling the latest whizz-bang electronic technology that is bringing us, among other novelties, virtual reality theme-parks (already established in Japan) and an ever increasing number and variety of "let's escape from reality" experiences for a fiver on what would otherwise be a dull Sunday afternoon. The new Tate at the former Bankside power station will be a more complex junction box than this, plugged into a high-voltage circuit of flats and houses, shops and cafes at the hub of a revamped transport system. Here is the art gallery as urban regenerator.

Does it need to fit so closely into the jigsaw of the city, or could it survive perfectly happily and in less than splendid isolation like any of Britain's degenerate, yet immensely popular out-of-town superstores?

The answer could be no, but only if the current boom in gallery-going is thought of as a short-term aberration that will dissipate as other forms of cultural entertainment win over a fickle and promiscuous public. But while superstores will soon be looked on as absurd architectural, ecological and retail dinosaurs, art is unlikely to wither in the coming decades, no matter how immune we become to the visual pranks and the hype that too often laps around the work of contemporary artists.

Viewed in the long term, ambitious cultural projects like the Tate Gallery of Modern Art can only enhance the fame and fortune of the cities they stimulate and, at best, grace. The new Tate promises to be the most important stimulant in reviving a run-down London borough (Southwark) and a bridge linking the fortunes of central London north and south of the Thames.

The Tate's decision to house its modern art gallery within the promethean walls of Bankside power station in Southwark on the other side of the Thames from St Paul's Cathedral encouraged developers to jump into a borough they have, to date, studiously avoided. Imagining (no doubt rightly) that the idea of living in a Soho-like loft next door to the Tate with views of the Thames is a particularly attractive one to the cultured and wealthy. Manhattan Lofts, developers of New York-style warehouse apartments, snapped up a big redundant warehouse for conversion into prime-site flats the moment the Tate decided to make a play for the old power station.

Meanwhile, under the forward-looking aegis of Jeremy Fraser (leader of Southwark council) and Fred Manson (the borough's director of environment and regeneration), new local planning regulations will ensure that buildings converted here in the wake of the Tate will include shops, cafes and other social facilities at street level. This will overcome one major problem from which the area suffers - single-use buildings that exist as if in a vacuum and have little or no relevance to the lives of local people. In fact, the Bankside quarter of Southwark is home to a plethora of dreary and secret new buildings in which latter-day clerks process cheques and bills and dream of going home as early as possible to the suburbs, as far from Bankside as possible.

Mixed-use buildings will help to overcome this particular form of urban dysfunction. So, too, will an influx of students. The London School of Economics opens a big student hostel this autumn in the former CEGB offices at the back of the future Tate. Meanwhile, the Globe Theatre is thatched and almost ready for action. The long-awaited Southwark Tube station (designed by MacCormac Jamieson and Prichard and possibly to be named Bankside when it opens in 1998) is on schedule, while the pedestrian bridge that may yet link Bankside to St Paul's and the City of London looks increasingly likely to spring into life.

Investment in low-cost housing for rent in the area is planned to balance the potential influx of arty-smarties with their modish clothes, frou- frou shops, private art galleries, novelty restaurants, cars and strident voices. The Tate plans to be very much a part of the local scene, not just in terms of being a great place to meet (which it will be if the architectural plans being developed by Herzog and de Meuron in Zurich turn out to be as coolly glamorous as they promise to be), but also in terms of being highly involved in local arts and education.

The vast spaces of the power station that the Tate will not occupy in its first years may well be given over to other cultural activities and institutions, so that Sir Giles Gilbert Scott's solemn temple of power becomes a powerhouse of contemporary arts from music and theatre to film, photography and architecture as well as the Tate's own artworks.

Open late at night, the Tate will be an integral part of the local cityscape and not isolated from it. It has the potential to draw millions of people and even more millions of pounds to this Dickensian patch of London. It will prove, in every sense, that art is not a plaything of the splendidly isolated wealthy, but a vibrant and lucrative catalyst in generating new life in old cities.

Oddly, the Tate has yet to hear from the Millennium Commission whether or not its bid for pounds 50m of National Lottery money has been successful. For here is a case of lottery money being used as a major, long-term investment in a run-down area and, at the same time, helping to create a world-class modern art gallery that will also serve to bring the arcane world of art down from Parnassus to the marketplace. And, in the process, create the most exciting and elegant brick box in Britain.