The two galleries raised £420,000 to buy the portrait, which has not been exhibited since 1883, with the help of generous donations from a number of organisations including The Art Fund and the National Heritage Memorial Fund.

The portrait of the Preston born industrialist will be on display at the National Portrait Gallery until January 2009 before moving to the Harris Museum & Art Gallery, Preston.

Sandy Nairne, Director of the National Portrait Gallery, said: “The Arkwright is an outstanding acquisition of a great pioneer, painted by one of the finest of British portraitists.

“I am delighted, with the Harris Museum & Art Gallery, Preston, that we have jointly been able to acquire this portrait and I am most grateful to all our generous supporters.”

Arkwright’s industrial inventions made him one of the early ‘cotton kings’ and the father of the modern factory system however he was later unflatteringly described as a ‘plain, almost gross, bag-cheeked, pot-bellied Lancashire man’.

Joseph Wright of Derby is considered one of the most original and important artists working in eighteenth-century Britain and the National Portrait Gallery has just two of his works in their collection.

Cllr Christine Thomas, Executive Member for Community Services at Preston City Council, said: “The Harris Museum & Art Gallery is the perfect home for the painting, enabling it to be shown as part of the museum's important collection of eighteenth century portraits and alongside the largest collection of objects which tell the story of the city and its place in the world.”

See www.npg.org.uk or www.harrismuseum.org.uk for more information.