LONDON -It lay forgotten for decades among a pile of dusty exercise books, pens and staplers in the back of an old school cupboard. But this painting – discovered by pupils of Roedean School in Brighton when clearing out an old headmistress’s office – could be worth up to £1 million. The painting was in a dusty package wrapped in plastic which they almost threw in the bin.

But when they unwrapped it they found a forgotten work by British painter John Constable. Titled The Chain Pier Brighton In A Gale, it is understood to have been painted when the artist, most famous for his masterpiece The Hay Wain, visited the seaside resort in the 1820s. On the rear is a bill of sale which states that the painting was bought from the artist’s grandson Hugh Constable and exhibited at the Constable Exhibition in 1900.

It was then auctioned in 1909 by Christie’s as a J. Constable R.A. and sold for £31 10s. It was sold by Christie’s at the same time they sold a much larger painting of the pier by Constable which is now in The V&A. Richard Chamberlain, Roedean’s senior deputy head, said: ‘A couple of the girls and I were waiting to attend a school event one evening and we were chatting outside the room that was, many moons ago, the headmistress’s office.

a woman standing next to a man in a suit and tie: The students Eris Kennish, 17 (left), Amirah Mehdi, 17 (centre), and Mary McHarg, 18 (right), found the painting along with the school’s senior deputy head Richard Chamberlain (centre). The painting was in a dusty package wrapped in plastic was almost thrown in the bin