A shared vision

The Tate has announced that it is buying a video installation by Bill Viola jointly with the Whitney Museum, New York, and the Pompidou Centre in Paris. The collaboration is believed to be the world's first substantial co-purchase by leading museums. It is a sign of the times. Has the funding crisis reached such a critical pass that major institutions are having to surrender cultural autonomy? Or is something more radical taking place, a shift that will alter the way we think about how museums should work?

There is no question that the allies have secured a major work of contemporary art. Five Angels for the Millennium, made a year ago, consists of five large video projections, each showing a serene underwater landscape that occasionally bursts into life as a human figure dives into or erupts from the water. Viola, who almost drowned as a child, engages with the biggest issues - life, death and the indefinable state in between - in five projections: Departing Angel, Birth Angel, Fire Angel, Ascending Angel and Creation Angel. In his Nantes Triptych (1992), also owned by the Tate, another figure floats underwater in the central panel, while the others portray a young woman giving birth and an old woman in the throes of death.

No artist has brought the medium of video closer to the history of painting - a development recognised in the august Metropolitan Museum of Art in New York, where his Quintet of Remembrance sits among Old Masters and Impressionists. Buying a Viola has become commensurately expensive. The museums are being tight-lipped about what they paid last month for Five Angels, but London dealer Anthony D'Offay was offering the work last year for around £400,000.

The institutions were quick to explain that money was not the only issue. It is a "space-hungry work", says Tate director Sir Nicholas Serota. Requiring up to 5,000 sq ft, it could not be permanently displayed by any museum without excluding other important works. This way, Five Angels can be regularly on display. The rotation arrangement has yet to be finalised, but it will probably spend a year or so in each museum. Nor is it a coincidence that the first joint purchase is a video piece rather than a painting. "It's just a case of transferring a set of DVDs," says Serota.

But the acquisition amounts to more than mere pragmatism. The modus operandi of museums has scarcely changed since 1753, with the founding of the world's first public collection, the British Museum. Its role was to acquire, preserve and display artefacts of cultural value, safeguarding them against changes in taste and fashion.

Today, under different pressures, a museum adopts other roles that make it more a site of cultural exchange than a permanent repository. Like any embattled entity, it must stay flexible and seek partnerships.

Joint purchase is a logical step in a conglomerate culture. But it bears obvious risks. What if one partner decides to sell? No one would dream of a break-up now, but a new regime in one museum a few years hence, or a change in government policy, might leave the other parties embarrassed. Serota insists they would have the right to veto any such sale.

And what of the competitive impact of three museums clubbing together? The deal takes two eager buyers out of the Viola market - already limited to public museums by virtue of the work's dimensions.

The artist is reportedly comfortable with the deal, relishing the blue chip covenant it confers. "You could argue that it would be better if we had [each] bought different works," admits Serota, "but none of the institutions could have found themselves with such a prime piece."

While three museums represent a formidable force, they are still minute when compared to private buyers, to whom they will anyway have to turn to support a purchase of this magnitude; both the Tate and the Whitney raised private cash for their stake in Five Angels.