It has been nearly three decades since the disappearance of one of the Spanish Royal Collection's most famous paintings.

Bodegon de Pesca, by 18th Century Spanish painter Bartolome Montalvo, vanished while on loan from the world-famous Prado Museum in Madrid, to a school in the southern city of Cordoba, in 1974.

Now the lost artwork has turned up in Sussex.

The museum had given up hope of ever seeing the painting, Still Life Of Fish, again after it investigations to find it proved fruitless.

Had a professional thief snatched the artwork? Or perhaps a young pupil sneaked the painting off the walls when no one was around?

The oil painting on wood was one of the first artworks to enter the renowned museum when it opened in 1819.

But whoever had taken the painting gave nothing away about its fate for all these years.

Nothing more was heard of it until it resurfaced at an auction house in Sussex.

Now, after an anonymous tip-off, the painting has been recovered and is to be reunited with Spain's flagship museum.

The Prado was thrilled at the news. A museum spokeswoman said: "We are very happy the painting has been recovered.

"It is very extraordinary for something like this to happen. It is like a fairytale."

Prado officials were alerted to the missing painting being offered for auction at Gorringes Auction Gallery in Lewes, East Sussex, in July.

Yet how did it find its way there? Philip Taylor, senior partner at Gorringes, helped provide a piece in the missing jigsaw.

He said: "One of our regular suppliers, a British antiques dealer in Marbella on the Costa del Sol, came to us. He sent the painting with a consignment of goods to sell.

"He had bought the painting as part of a flat clearance from a Spanish woman in June.

"Because he was a regular, we catalogued the work and put it in our auction catalogue."

The auction house had no idea of the painting's slippery past. It was not signed. Gorringes simply described it in the auction catalogue as "Spanish School".

Mr Taylor said: "To be honest, we didn't think it was anything special and wouldn't have expected it to make more than a few hundred pounds. We had no reason to suspect anything out of the ordinary."

The woman who sold the painting to the Marbella dealer turned out to have worked as a caretaker at the Cordoba school.

A spokesman for the Spanish Police said: "In 1974, because construction work was being done at the school, she took the picture and kept it at her home until the sale."

The British antiques dealer surrendered any claim to the work when he was told the painting belonged to Spain.

The Prado spokeswoman added: "We are very pleased about the painting being recovered because it was one of the very first to arrive at the museum in 1819."

Now the riddle has been solved, Still Life of Fish may, once again, see the light of day.