David Hockney donates his largest work ever to the Tate Gallery

David Hockney is giving the largest painting he's ever created to the nation. Entitled Bigger Trees Near Warter, the 40ft by 15ft work - made up of 50 separate canvases - will hang at the Tate Britain in London. Hockney, who recently returned to live in Yorkshire after decades spent in California, said: "There are two galleries in the world I have enormous affinity for - the Los Angeles County Museum, and I've given it work, and the Tate.

"America is already enriched with gifts but that is mainly because tax breaks make it easier for living people to give. It's harder here."

The Tate, which already owns more than 100 conventionally-sized Hockneys including two of his best known - A Bigger Splash and Mr and Mrs Clark and Percy - will make a formal announcement about the gift next month. It is hard to put a value on the work: recent Hockneys have sold for between £2m and £3m, but the sheer size of this work makes it unique.

It was first seen by the public last year at the Royal Academy summer exhibition where it filled the end wall of the largest gallery. It depicts a copse of trees beside a country road in the East Riding of Yorkshire, near Hockney's studio in Bridlington.

Hockney and his assistant, Jean-Pierre, used computer technology to help map out the 50 separate canvases. But it was then painted in what the art critic Martin Gayford, one of the first to see the finished work, called a "breathless, three-week sprint that left Jean-Pierre looking exhausted and the painter himself exhilarated. Both had grown beards; as a result Hockney slightly resembled Cezanne."