Andrew Lambirth looks on as Gateshead's `Angel' finally takes wing

What is the purpose of public art? To please people or arouse controversy? Antony Gormley's Angel of the North rears against the skyline of Gateshead like a crucifixion. What does it represent? Sited atop an extinct colliery, it is intended to symbolise the glories of Britain's industrial past and hope for its future, but does it really do this?

Gormley has said of an earlier version of the piece, entitled A Case for an Angel, that he didn't want it to be symbolic. "I want the work to be as actual as it can be, which is why my version of an angel is a rather uncomfortable mixture between aeronautics and anatomy."

Indeed, this great winged figure looks more like an aeroplane than an angel. From a distance, it appears remarkably modest, though it stands 65ft tall, with a wingspan of 175ft. From the train, a view of it is impeded until you are almost on top of it. From the road, it looks far more spectacular, though a clump of tower blocks is too close for comfort. Seen from its foot, looking up, the sheer bulk strikes home, coupled with an elegance of outline - the profile is meltingly sinuous. But of course it is the scale that principally engages.

Gormley's body-case sculptures, of which the Angel is a gigantic version, are cast from his own body. This might be thought faintly blasphemous when the sculpture is supposed to depict an angelic being, but no more so than a Renaissance artist painting his girlfriend as the Virgin Mary. Gormley creates a challenging image that is not intended to bring comfort, but to confront existence.

Nothing on this scale has been built in Britain before. Brancusi's Endless Column in Romania stands 96ft high but it doesn't have the mass of the Angel. Yet why did Gormley make the wings so huge? If the figure didn't look so balanced, you'd think they were out of proportion to the body. They act as a kind of barrier - like the gate that comes down at a level crossing when a train is due.

The pose is hieratic, like a priest offering thanks to God, but the face, with its lack of features or expression, is vaguely menacing. It's a contradictory sculpture, at once firmly grounded but also aspiring heavenward. Is it neutral or anguished? (Gormley generally does a good line in anguish.) The Angel is isolated. Even suppose it could come down from its hilltop, its wings are too wide to go through the door if you invited it home. It is, in fact, the perfect stuff of legend. Perhaps, like the Cerne Abbas giant, it will inspire pilgrimages - but for those seeking enlightenment, rather than fertility.

Perhaps the Angel best signifies the cultural renaissance currently emerging on Tyneside - Gateshead's Baltic flour mills are about to be transformed into a pounds 46m international centre for contemporary visual art, with a Norman Foster concert hall complex adjacent. If the main point is to attract attention to the area and to engage people in debate, the Angel will be a great success.