ARCHITECTURE : Free spirit

Three things about the Serpentine gallery: it is small, exciting and free. It is being revamped; it should be cloned.

Julia Peyton-Jones. There's a tongue-tripping name to conjure with. How do you imagine Ms Peyton-Jones? A heroine from an Ivy Compton- Burnett novel, a tennis-playing, wholly-to-my-liking gel from a John Betjeman poem? You wouldn't be far wrong. But if you thought the bearer of such a perfectly constructed double-barrelled name was in any way pompous and grand - and when you learn she is the director of an art gallery, you could be forgiven for thinking so - you couldn't be more wrong.

Peyton-Jones is the energetic and delightful director of the Serpentine Gallery in London's Hyde Park. The Serpentine - apart from having a delightful name, too - is the only publicly funded contemporary art gallery in central London that is free of charge and open seven days a week during exhibitions.

The country needs more Serpentines, public and public-spirited galleries that we can afford to run without admission charges and which can bring art to all. Some of these might be brand-new buildings designed by young architects in parks and woods, but we must campaign for these and support those like Julia Peyton-Jones for whom art and architecture truly belong to everyone.

I know for a fact that the exhibitions it has held over the past five years have brought the work and sensibilities of some of the very best, and most bizarre, artists working today into the lives of people for whom Art has always been something rather frightening, or snotty, or simply a bit crazy and something to be avoided. It can be, but is more the fault of the Art World than of artists and art.

Peyton-Jones came to the Serpentine in 1991. Since then attendance at this romantic former Royal Park's tearoom has more than doubled. Last year it wooed 368,000 visitors, which compares very favourably with its big sister, the Hayward Gallery at the South Bank Centre (230,000).

The reason why is not too hard to find. Peyton-Jones and her team have made a point of showing the work of controversial artists, of courting the media (not always favourably), of winning and losing the Princess of Wales as patron, and, as the art critic Richard Wentworth puts it, Peyton-Jones is "the angel who has led a great swathe of the stuffy middle- class out of Peter Jones and into art".

More than that, Mr Wentworth, she has encouraged a swathe of people who cannot afford to shop in Peter Jones to come in and look at art, from Damien Hirst's pickled sheep to Helen Chadwick's fountain of chocolate and "piss flowers", Jean-Michel Basquiat's graffiti art and the actress Tilda Swinton sleeping in an exquisite glass case. This is the sort of art that gives Brian Sewell apoplexy, but it is nevertheless enjoyable, provocative and even strangely beautiful.

Peyton-Jones, by the way, is not one of those unthinkingly cruel Art World people who signed an infamous letter to the editor of London's Evening Standard trying to undermine the career of one of Fleet Street's best journalists. She sails above intelligent attacks and fierce criticism; yet, there is no doubt that she has, whatever she says, courted controversy, and this has given the Serpentine a profile out of scale with its Liliputian parkland architecture.

Now the gallery is about to grow. Closed until next September, the Lutyens- like building (designed by J Gray West, chief architect to the Office of Works, 1934, and Grade II listed) is being gently vamped by John Miller & Partners, sober and intelligent architects who have been quietly extending the Tate Gallery on London's Millbank and did a good job enlarging the Whitechapel Art Gallery 10 years ago.

Their task is a tricky one: finding new space for showing art and for offices without straying beyond the bounds of the existing fabric. When finished, there will be a new entrance, an enlarged bookshop, an education studio, a workshop and storage facilities, as well as proper security and climate control ... heaven on earth, and all for pounds 4m, with pounds 3m coming from an Arts Council Lottery grant and the other pounds 1m raised through charm and sponsorship.

Meanwhile, the staff are housed in a Knightsbridge office block, courtesy of the men (and women) from the Pru, and the gallery will show work amid the building works by the sculptors Rasheed Araeen and Bill Culbert.

The most important thing about the sparkling new-look Serpentine is that entrance will still be free and it will continue to encourage those who know nothing about art, old or new, to come and look. "The Serpentine must always be free," says Peyton-Jones. "The idea of charging entrance fees to public museums and art galleries is terribly sad. It will stop people like you and me popping into them on the spur of the moment to see a favourite painting or to see a show we might otherwise have given a miss because we weren't convinced that we really wanted to see it, and it will keep the people who don't have the money from engaging with art. I think the current obsession with charging is a terribly retrogressive and damaging step, and particularly because we have the money, through the Lottery, to spend on funding our museums and galleries in the long- term."

We share childhood memories at this point: neither of us were brought up with art, and what we began to see we saw for ourselves. "Without the free museums and galleries, I don't know how you or I would have encountered art until much later in life, if at all. I feel very strongly that we are making a big mistake and taking art away from the people just as more and more of them are coming to terms with it."

Peyton-Jones admires the work of those public-spirited authorities, organisations and individuals who, in the course of this century, have done so much to bring art down from Parnassus to the marketplace, and she does not mean the sellers who hang their wares along the railings of Hyde Park along the Bayswater Road. She admires the work of the one-time London County Council, of Frank Pick and London Transport (which did more than anyone or anybody more than half a century ago to create art for all); she is grateful to Westminster City Council and the Arts Council for continuing to support a wayward and tiny gallery that Ian Sproat, then number two at the National Heritage department, wanted to close and turn into riding stables in the early Eighties.

To this extent, small has been beautiful. A major gallery may well feel forced to introduce admission charges to pay for its new buildings and its Damoclean overheads. The Serpentine is small enough to be cheap to run, small enough to be flexible in its programme and small enough for visitors to be fond of it in a way that they can never truly be fond of major national and municipal galleries.

"The smallness of the Serpentine helps too," says Peyton-Jones, "in allowing us to keep as free as we can from Art World politics. The staff and directors of major galleries have to struggle with the sort of politicking and professional jealousies that we can, to a large extent, steer clear of. But without patronage we would get nowhere. I've tried as hard as I can to make the Serpentine a friendly place. I know we've been criticised for being a little too Hello! or Tatler-ish, but I've wanted to get people excited about contemporary art from right across the board. It would be no good having the Peter Jones set without having an appeal to the sort of people who normally never think of spending an afternoon looking at art. If people come in just to keep out of the rain - which they do - we want to win them over."

The architectural lesson of the Serpentine is clear: when internicene politics, uncertain politicians and professional rivalries threaten to stop things happening, think big on a small stagen