A miniature portrait of the man thought to have inspired one of Jane Austen's most famous literary characters - Mr Darcy - is going on sale.

The image is a watercolour of Thomas Lefroy, who the novelist is said to have loved in her youth. It was painted on ivory in 1798, two years after the couple parted because Lefroy was expected to marry a wealthy heiress.

Austen and Lefroy's relationship was played out by Hollywood stars Anne Hathaway and James McAvoy in last year's movie Becoming Jane.

Some experts believe that not only was Lefroy material for the creation of the handsome, intelligent Mr Darcy in Pride And Prejudice, but his family provided Austen with inspiration for the basic plot of the novel.

Only two versions of the painting by English miniaturist George Engleheart are thought to exist. The item to be sold by dealers this month at the Grosvenor House Art and Antiques Fair is expected to fetch £50,000.