Fowl play

Katharina Fritsch takes a sip of her mint tea, leans in close and - in a voice full of mischief - says: "I think the English have a great sense of humour. I know they like to play games with language. They like their double meanings. So I wanted to play around."

The German artist, bleary-eyed in a London hotel after getting only two hours' sleep on an early flight from Dusseldorf, is talking about her sculpture for the fourth plinth in Trafalgar Square. The moment she was asked to submit an idea, she knew what it would be: a big blue cock. Sorry, a big blue cockerel.

Fritsch's winning commission - an oversized rooster 4.7 metres tall painted a deep matt blue - was unveiled recently, positively inviting double entendres as it sits there in the shadow of Nelson's Column. And that, of course, is part of the point. There is certainly a delicious, childish pleasure to be had in seeing a sculpture called Hahn/Cock (hahn means "cock" in German and carries the same double meaning) in such an august location, waving his tail-feathers at the National Gallery and aiming his beak at Nelson's sniffily turned back.

There's humour, too, in the fact that a cockerel - the national symbol of France, especially when coloured a distinctly Gallic hue - will reside for the next 18 months right beside a monument to the vanquishing of the French. Is this irony intentional?

"I definitely never thought about the French thing," Fritsch says. "But it's a nice humorous side effect to have something French in a place that celebrates victory over Napoleon." She gives an impish smile. "He has come back as a cockerel!"

Humour runs through much of Fritsch's work, which is well-known in Britain: she was the subject of a major show at Tate Modern in 2001, and is represented by influential gallery White Cube; but she is much more famous in Germany. Since the late 1970s, when she began studying at Dusseldorf's prestigious Kunstakademie, where she now teaches, she has turned out a series of meticulously rendered sculptures of animals and people, their detailed naturalism made strange by spray-painted colours that are garishly unexpected and uniformly matt.