Hidden regional treasures take a trip to town

"It was lying in a velvet-lined box," recalled Jane Martineau, a curator at the Royal Academy. "We were led down into a basement in Rochdale to look at it. I had not even known it was there before we arrived - a gold-backed crucifixion scene."

For Ms Martineau the unlikely discovery in a Greater Manchester cellar of a 14th century altarpiece by a Sienese artist was one of the highlights of months of visiting galleries and museums and selecting works to show in the Academy's new exhibition, Art Treasures of England: The Regional Collections, opening in London on 22 January.

Among the attractions are paintings by Canaletto, Gainsborough, Hogarth, Stubbs, Constable, Monet, Degas, Renoir, Bacon and Hockney, and sculpture by Brancusi, Hepworth and Henry Moore. The show, aiming to highlight the number of works of art to be found across the country, is sponsored by the Third Division football club Peterborough United.

The discovery of the altarpiece by Giovanni di Paolo is typical. It is a work of superb craftsmanship which has not been shown for 17 years because of humidity problems.

"We didn't just want the famous things," Ms Martineau said. "It was a question of having a cross-section from all the galleries. We listened to suggestions and we tried to find a way to show how the galleries' collections had grown, as well as what is hidden inside them."

The long process was not simply an exercise in London-centric plundering. Instead, the Academy's exhibition aims to celebrate some of those national works of art which are rarely, if ever, seen in the capital. And sometimes not anywhere else either.

Among the best-known images in the show are When did you last see your father? by Frederick Yeames from The Walker Gallery in Liverpool, William Blake's The Ancient of Days from the Whitworth Art Gallery in Manchester, Jockeys Before the Race, by Degas from The Barber Institute in Birmingham and WP Frith's The Railway Station from Royal Holloway College, London.

"Due to dire financial straits many of these galleries just can't afford to show a lot of the pieces they have and so some have been hidden away for quite some time," Ms Martineau said.

"The hope is that the exhibition will encourage people to go back and look at their own gallery more closely."

The team of three selectors consciously steered away from the more recent works they were offered.

"While the modern pieces at Swindon and Southampton were great, and we did take a Gilbert and George, I think on the whole, because of the fact we have just had Sensation in the gallery, we stopped short of artists such as Rachel Whiteread and went instead for a decade or two earlier: for Peter Blake, for example, who was working in the Sixties."

Consequently the 400 final choices, from more than 100 venues around the country, largely reflect the exuberant period of art acquisition in the 19th century, an era of confidence, particularly in British art, which is perhaps only equalled by the current mood.

Peterborough United's chairman Peter Boizot, the multi-millionaire founder of Pizza Express, is an enthusiastic patron of the arts and there was no reason, he felt, why sport should not offer a helping hand to culture, especially now that the two share the same government minister. In return for sponsorship the club's name features on all programmes and posters.

"The local paper did a picture of the Mona Lisa wearing our scarf and they had the manager, Barry Fry, as The Laughing Cavalier."

Mr Boizot stepped forward with more than pounds 100,000 funding for the show when he realised that the Academy was having trouble. At first, he simply helped the curators by contacting other league clubs around the country, but when the response was poor the entrepreneurial chairman decided that Peterborough alone should reap the benefits of being the first club to sponsor a major art exhibition, especially since the team's own local gallery is lending several works to the show.