Mystery donor offers Tate £12.5m to buy Reynolds portrait

A mystery donor is prepared to give £12.5m for Britain to retainone of its most important paintings of the 18th century.

The unnamed benefactor told the Tate on Monday that he was willing to write a cheque for Portrait of Omai by Sir Joshua Reynolds, the first president of the Royal Academy. The work, which is regarded as a masterpiece, shows the first Polynesian to visit England, where he was fêted by London society.

The Tate is eager to buy the painting, which it sees as an important social and historical document as well as a beautiful work, and, with the support of the National Art Collections Fund charity, was due to launch a fund-raising drive when the offer was made.

Sir Nicholas Serota, the galleries' director, said he felt "astonishing excitement and an incredible relief" when he took the donor's call. "The picture has an incredibly powerful resonance here in this country that it would not have anywhere else in the world and that is why we have been so determined to acquire it," he said.

But he stressed that the purchase had still to be finalised. "It's not often that you're able to announce a dramatic twist of this kind, but the story is not yet complete. I doubt this will be the end of the story."

The question remains whether the owners will sell. A London dealer, Guy Morrison, bought the painting at Sotheby's two years ago and then sold it to a Swiss company, which will now be asked to accept the matching offer of £12.5m.

The firm, Settlements SA, has previously indicated it would consider an offer, but had stunned art lovers by refusing to allow the work to go on public display while attempts to match the price went ahead. Settlements SA could still refuse to sell, although that would carry the risk that a furious Government could refuse to grant an export licence.

David Barrie, director of the National Art Collections Fund, said with funding for the portrait secure, the fund would turn its attention instead to campaigning for urgent reforms to prevent such crises in future.

It wants the Government to restore funding of the National Heritage Memorial Fund to its pre-National Lottery level of £12m. The fund is one of the few other bodies to which galleries can turn for help.

It also wants to improve tax incentives, including allowing donors to offset gifts of works of art against tax. The donor in this case will receive no tax benefits.

"Obviously, it's great news that this extraordinarily generous benefactor should come forward but, sadly, this isn't likely to be repeated very often," Mr Barrie said.

A Tate benefactor, Edwin Manton, has given about £15m towards development works, but the offer announced yesterday is the biggest amount by far for a single work. Sir John Paul Getty gave a £50m endowment to the National Gallery some time ago to help its acquisitions budget.

Sir David Attenborough, who is chairing the Art Fund's centenary celebrations this year, said in reference to Omai: "He came from a world that was as remote to 18th-century Britain as the Moon is today." Omai learnt to skate, went to hear the music of Handel, and dined with the Royal Society before returning to the South Seas.

Artworks saved by philanthropists

THE MAPPA MUNDI

John Paul Getty donated £3m to the £7m needed to secure this rare 13th-century map of the world, which became a cause célèbre in 1989 when Hereford Cathedral put it on the market to raise finances for the cathedral's upkeep. The map would probably have gone abroad otherwise.

'OPENING OF WATERLOO BRIDGE', BY CONSTABLE

Saved for the Tate in 1987 with an assortment of grants from bodies including the National Heritage Memorial Fund and National Art Collections Fund. But a major contributor was the philanthropist Vivien Duffield, who gave £430,000 towards the £2.9m asking price.

'PORTRAIT OF SIR WILLIAM KILLIGREW', BY VAN DYCK

Christopher Ondaatje, who came to public attention for funding the extension to the National Portrait Gallery, gave £100,000 towards the £1m asking price for this portrait of the 17th-century playwright last year. It is on permanent display at Tate Britain.