ART experts believe schools all over the country could unknowingly be sitting on valuable paintings worth millions of pounds.
The claim came after a painting that hung virtually unnoticed in a Welsh school corridor was this week sold for pound;200,000.
Bought for pound;250 by Llantarnam comprehensive in Cwmbran, near Newport, in 1954, the study of three girls picking apples is by Victorian artist George Dunlop Leslie and was exhibited at the Royal Academy in 1883.
The money raised by the painting, sold through Sotheby's in London to a private collector in America, will fund a new classroom block for the school, which is 150 pupils above capacity.
There have been several similar stories in recent years. Art specialist Rupert Maas, a presenter on BBC2's Antiques Roadshow, said: "I often hear about schools that suddenly realise the value of a piece.
"The fact is that many of them are given as gifts so the school has never really found out exactly what it is or how much it is worth. It is only when some expert happens to see it and recognises its worth that the school chooses to have it valued."
Chris Proudlove, of Sotheby's, added: "There are undoubtedly schools with paintings and antiques in their corridors, the value of which might come as a big surprise to teaching staff.
"For example, we recently sold Leonardo da Pisa's altarpiece of the Virgin and Child enthroned for pound;84,000 on behalf of the governors of Saint Felix school in Suffolk. The proceeds were to go towards the school's new sport and theatre complex."
Last year, Marlborough College, the Wiltshire independent school, sold a donated Thomas Gainsborough painting to a charitable art foundation for pound;3 million. The move sparked controversy over whether schools should raise funds by selling off gifted art.
But it is not just public schools that boast impressive art collections. The Barclay school, a Stevenage comprehensive, is the proud owner of the original of the famous Henry Moore sculpture The Family Group.
Headteacher Russell Ball said: "It was originally destined for a community college in Cambridgeshire but when they turned their noses up at it, Henry Moore donated it to Sir John Newsome, then the chief education officer for Hertfordshire. He in turn handed it to us.
"Having such a special piece of art is an inspiration to all our work and it is used in many of our curricular activities, including English, art and even technology."
The art in many schools is owned by their local education authority, some of which have collections worth hundreds of thousands of pounds.
Hertfordshire's education dep-artment owns more than 1,500 items that are loaned to schools in the area.
Peter Dawson, county advisor for art and design, said: "Our collection was started by Sir John Newsome after the Second World War. He was adamant that children had access to original pieces of art. "We have all kinds of works including pieces by big names such as Barbara Hepworth, Peter Blake and John Minton.
"The collection is probably quite valuable but we are not interested in the money or selling it. It is there to stimulate the children in all they do."