A Joshua Reynolds' portrait of a Welsh heiress who co-founded England's first public art gallery has been found after a 70-year hunt.

The painting of Margaret Morris by Sir Joshua Reynolds was done around 1757 and was kept by her family until 1930 when it was sold for �5,000 to an unknown American bidder.

The gallery has been searching for the painting ever since.

Morris provided the crucial funding to establish Dulwich Picture Gallery, south London, following the death of her husband.

Press campaign

Her sarcophagus lies in the gallery's mausoleum.

After the picture was sold, Dulwich College commissioned what the gallery called "a rather dismal copy" by Moussa Ayoub, which has been hanging at the gallery since.

A renewed press campaign in 1998 to find it resulted in a phone call from America, claiming the mafia had it.

Earlier this year, however, the gallery's curator, Ian Dejardin, received a call from the west of England.

The called said: "We've got a picture of a Margaret Morris and the note on the back says she was married to your founder.

'Excellent condition'

"It's by Sir Joshua Reynolds. Would you like to come and see it?"

Kate Knowles, the gallery's development director, said: "We rushed straight to their house in the west country.

"When no-one answered the door bell, we peered through the window, and there it hung in excellent condition."

The anonymous owner is the grandson of the buyer from 1930.

He has bequeathed the work to the gallery in his will and loaned the work in the meantime.

Reynolds was the leading 18th Century portrait painter and the first president of the Royal Academy.

Last year Reynolds' Portrait of Omai sold for more than �10m at a British auction.