Public appeal for Turner painting

The Blue Rigi depicts the mountain as seen from Lake Lucerne

Tate Britain is asking the public to help save one of JMW Turner's finest watercolours for the nation.

The Blue Rigi was sold at auction last June to an anonymous bidder for £5.8m - a record for a British watercolour.

It is currently barred from leaving the country under an temporary export ban imposed to give the Tate time to raise the £4.95m it needs to buy it back.

The Tate wants members of the public to contribute £300,000 of that total by donating £5 to "buy a brushstroke".

Several leading artists, including David Hockney, Peter Blake and Rachel Whitbread, have already bought brushstrokes to support the appeal.

'Huge shame'

Tate Britain has pledged £2m of its own funds towards securing the painting, and has also been given £500,000 by the Art Fund charity.

"There is very little chance of Tate ever acquiring another Turner watercolour of this stature again," said director of the Art Fund, David Barrie.

Attempts to buy The Dark Rigi last year were unsuccessful

"It would be a huge shame if we didn't do everything we could to secure it for public enjoyment for generations to come."

The Blue Rigi is one of a series of four watercolours Turner produced in 1842 after returning from a trip to Switzerland.

It features Lake Lucerne and the Rigi Mountain at sunrise, and was bought by its first owner in 1842 for 80 guineas.

The Tate already owns Turner's preparatory sketches for the Rigi series, but attempts to secure The Dark Rigi failed last year when it was sold to the National Gallery of Art in Washington for £2.7m.

An exhibition featuring the Blue Rigi, Red Rigi and Dark Rigi is being held at Tate Britain from 22 January to 25 March 2007.