German researchers believe they have found the legendary Amber Room, thought to be most valuable piece of art stolen by the Nazis during the Second World War. The ornate panels, embellished with amber and gold leaf, were gifted to the Russian Tsar Peter the Great in 1716 and are estimated to be worth €250m (£224m).

Mystery has surrounded the whereabouts of the Amber Room for the last 70 years. Now, three treasure hunters say a series of clues has revealed the room to be hidden in a network of tunnels under a cave in the Ore Mountains, eastern Germany. Leonhard Blume, 73, Peter Lohr, 71 and Günter Eckhardt, 67, examined witness reports complied by the Stasi and KGB.

They then used radar to see what lay beneath the so-called "Prince's Cave" outside Hartenstein, a town close to the Czech border.  "We discovered a very big, deep and long tunnel system and we detected something that we think could be a booby trap,” Mr Blume told The Times.

Evidence of an explosion fits with witness accounts that a shipment of crates had been hidden in the tunnels and the entrance blown up to hide them, he said. Now, the three men are seeking funding to excavate the site. “We want to go on but it’s all very complicated and we need a sponsor,” Mr Blume said.

The East German and Russian secret police each spent a decade hunting for the Amber Room. Historians are divided on its fate. Some believe it was destroyed in an air raid on Königsberg in 1944, while others think it was destroyed by Soviet soldiers at the end of the war.

According to