THERESA THOMPSON talks to Turner Prize-winning artist Mark Wallinger at the unveiling of his sculpture Y at Magdalen College

What connects ancestral willows in a quiet meadow in one of the most visited and beautiful of Oxford colleges, antlers, divining rods and Gothic tracery, with a former YBA famed nationally for a replica of an anti-war protest and locally for the Tardis on an Oxford lawn?

But before this begins to sound like Round Britain Quiz, let me explain.

Mark Wallinger, one of Britain's foremost contemporary artists, was in Oxford on July 22, St Mary Magdalen Day, to unveil his first-ever dedicated permanent public artwork: Y', a 10m-high metal sculpture of a tree in the grounds of Magdalen College commissioned to celebrate the college's 550th anniversary.

Wallinger, who is perhaps best known for winning last year's Turner Prize with State Britain, a reproduction of all the paraphernalia of Brian Haw's anti-war protest in Parliament Square, and for Ecce Homo, a life-size sculpture of Christ that occupied the Fourth Plinth' in London's Trafalgar Square in 1999, admits the commission was "a daunting task".

Wallinger explains: "I was asked two years ago to create something for this ancient seat of learning. Something for that kind of man-made nature that places like this do so well. When I visited the college I was struck by the deer park, the water meadows, the Gothic tracery in the college architecture. I got thinking that the college goes back 17 generations. I wanted to make something emblematic of all of that, something that had echoes of its architectural features - and a growing, learning, yearning, reaching out sort of feeling. I began to think round the idea of generation, of the trees and the antlers of the deer.

"It had to have its own presence and authority, to have that bit of magic," he added.

Y achieves this. There is an unexpected artlessness about this elegant, non-trendy, non-threatening piece of contemporary art that I have no doubt will stand the test of time. You could easily miss it, half-hidden as it is in tranquil Bat Willow Meadow at the far end of Magdalen's grounds, blending in with its surroundings. And for a solid sculpture it is oddly organic, completing a circle of willows, having roots' (its foundations are as deep as the tree is high) and sparkling', I'm told, in certain lights.

Painted pearl mouse grey, the colour chosen from swatches Wallinger brought with him on return visits, it is as much like the willows as he'd hoped, he told me.

"I wanted it to pick up on the changing light, sufficiently like raw steel but an organic silvery green-y grey: the base colour of the willows."

d=3,2,1I liked Y. It works on many levels, including provoking debate; it has already drawn numerous allusions. Its repeated bifurcating forks reference the branching college trees and antlers of its deer, Gothic tracery, lineages, and divining rods typically cut from willows, but, at first glance, it looked to me like a cross between a snow flake and a tree. Then, looking again, I saw an efflorescence of hearts' spreading from its centre; then, a diagram of the brain. Others meantime discussed its mathematical roots - Wallinger used the Golden Section as its proportion - and saw it in terms of XY axes, and Y chromosomes passed on through generations.

In moments the design had conjured up the magical and the mundane - and given pleasure to many.

"It's important it works viscerally for everyone," said Wallinger, who is considered one of Britain's most intellectually curious and socially committed artists. Drawing upon many sources, his art often reveals his interest in metaphysics, in systems of belief, and Englishness'. So many disparate ideas seem to fit together in this work. Prefigured? Or serendipity? A mix, Wallinger replied. "It's nice when serendipity interposes into proceedings."

Anthony Reynolds, who has represented Wallinger since his student days and whose London gallery is known for discovering exceptional young artists, said: "Serendipity happens uncannily often with his work. Layers of meaning seem to fall into place."

Born in 1959 in Chigwell, Essex, and now living and working in London, Wallinger was one of the original YBAs (the Young British Artists of the late 1980s), exhibiting at the Saatchi Collection, and at the Royal Academy's Sensation exhibition in 1997.

Locally, you may recall the Tardis - or to give its proper title, Time and Relative Dimensions in Space. Exhibited in 2001, this was Wallinger's only previous public artwork in Oxford: a pair of mirror-finished police phone boxes, one on the lawn outside the University Museum of Natural History, and, lo-and-behold, there again beside the dinosaurs once you were inside.

The £120,000 commission was supported by Arts Council England and the Henry Moore Foundation, with the generous assistance of Roger Kay, a member of the college, and his wife, Izabella. Wallinger was chosen from a short-list of UK artists drawn up by Paul Bonaventura, Lecturer in Fine Art at Magdalen and Senior Research Fellow at the Ruskin School of Drawing and Fine Art.

David Clary, Magdalen's President, says they were "a bit bold" in commissioning the artwork. "We have many fine artworks in the college, but little of the 20th century and none at all from the 21st. We wanted a permanent work that is representative of modern art in 2008, and something that everyone can enjoy."

They will, students, fellows and visitors alike. It is ten minutes from the centre of the college along the beautiful tree-lined Addison's Walk, and as David Clary emphasises, "Oxford residents can visit Magdalen College Gardens for free to come and look at the new sculpture."

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