Her winning works are both figurative and abstract and include a three- piece series, Sometimes A River, based on six-week's observations of the outback. Another work, Gibber Desert Constellation, depicts a stony desert without sky.
The artist, the daughter of novelist Frederic Raphael, is best known for her portraiture, and her work can be seen in the Fitzwilliam Museum, Cambridge, and the Metropolitan Museum, New York.
Raphael said: "I'm absolutely thrilled ... You never expect to win things but you have nothing to lose by entering competitions. What matters is that you feel you are getting better - it is dangerous to think of awards meaning a great deal but this is just really nice."
Her studio is a tranquil converted coach house in Camberwell, south- east London. "It's a lovely spot because no one knows I'm here. I discipline myself to painting every day, it's like any other job," she said.
Frances Borden, 25, of Bampton, Devon, won the pounds 10,000 second prize. Charlotte Sorapure, 27, of Blackheath, south London, and Sarah Florence, 32, of Norwich, shared the pounds 5,000 award for third place. A student award of pounds 1,000 went to Harriet Barber, 27, of Blandford, Dorset.
The judges included Lord Gowrie, chairman of the Arts Council, and Tim Clifford, director of the National Gallery of Scotland.Reuse content