It started over a decade ago, when Prince Charles accused a hapless architect of trying to build a "monstrous carbuncle" in his beloved Trafalgar Square. The National Gallery's extension turned into a farrago. Gallery renovations of all sorts became news.

At present, you can run round London's most interesting contemporary gallery extensions in an afternoon. But come the next century, it looks like the trip may take you more than a week.


CLORE GALLERY, Tate Gallery, Millbank (James Stirling, 1985)

Toytown doorways and windows, gaudy railings, beigey pastelly walls: utterly Eighties, but an exceptionally solid Ur-Eighties, a building which makes you think through why you hate postmodernism, and then think again.

SAINSBURY WING, National Gallery (Robert Venturi, 1991)

In a 1966 manifesto, the American Venturi suggested that brave new architectural futures could be found by ironically reinterpreting the past. A quarter- century later, Prince Charles seemed satisfied with the vaguely Corinthian carbuncle he grafted onto Trafalgar Square. But really, it just looks like a new building posing as an old one.

SACKLER GALLERIES, Royal Academy (Norman Foster, 1991)

High Tech is too imprecise a term for this breathtaking glass-and-steel structure, which appears delicately to balance on the edge of an excavated 19th-century wall. You whiz up in a trendy lift to be suffused in soft- white light: like heaven, with Michaelangelo's Holy Family at the top.


TATE BANKSIDE: Trendy Swiss firm Herzog and De Meuron moves into Giles Gilbert Scott's old downriver power station in Southwark.

Money: pounds 106m, with pounds 50m in place from the Millennium Fund, pounds 12m from English Partnerships and pounds 1m from Southwark Council.

Deadline: Building has just started; aims to be finished by 2000.

ICA: Will Alsop is suggesting a curious bulbous object, to rest on in situ piers at Blackfriars.

Money: Around pounds 30m is mooted. Lottery bid will go in next year.

Deadline: "2001 would be poetic, and yes, I suppose it does look a bit like the bone from the film."

V&A BOILERHOUSE: Daniel Libeskind's deconstructivist heap of boxes has been upsetting a lot of people since May. The architect is currently working on the "thunderbolt" Jewish Museum in Berlin.

Money: Roughly pounds 42m.

Deadline: Around 2001, but planning permission may be a problem with an HRH-unfriendly design like this.

WALLACE COLLECTION: The inner courtyard is a haven of ornamental-garden oddness. Rick Mather Architects propose floating a glass floor over the top of it and sticking a cafe underneath.

Money: A quarter of the pounds 10m budget was pledged 10 days ago by an anonymous donor. A Lottery bid is in for the rest.

Deadline: 2000, to mark the Wallace Collection's centenary.

DULWICH PICTURE GALLERY: London's oldest public gallery, designed by John Soane in 1814. Rick Mather Architects propose a cafe and education block, plus a bronze-and-glass cloister-cum-pergola on the side.

Money: Probably around pounds 8m.

Deadline: Expected to start building in 1999.

SERPENTINE: John Miller's blueprint "walks within the footprint" of the 1930s building, sinking workshops into a new basement.

Money: pounds 3m from Lottery, pounds 1m raised elsewhere.

Deadline: Work should finish next year.

NATIONAL PORTRAIT GALLERY: Jeremy Dixon and Edward Jones, of Royal Opera House fame, fill a dingy courtyard and add a rooftop cafe.

Money: pounds 14m to be funded by Lottery bid and 1896-1996 centenary appeal.

Deadline: Building starts in 1997, aimed for completion in January 2000. JT