A TEAM of snowboarding geophysicists have found the tunnel 67 German soldiers dug to escape from their prison camp in Bridgend in March 1945.

A documentary filmmaker asked Cardiff-based company Terradat to try to locate the escape tunnel, one of two the prisoners dug, at the Island Farm prisoner of war camp - the scene of the Welsh Great Escape.

The team, which also runs a popular website used to forecast when snow will fall at ski resorts, had to locate the tunnel without digging up the area around the one remaining prison hut. It used radar technology to search for the tunnel.

Project leader Nick Russill said, "They weren't even sure there was a tunnel there. It was just a bit of folklore."

A "small void" was detected two metres below ground level, near a depression which locals called the "exit shaft".

Before exploring further, Mr Russill met with two of the German POWs, Gerhard Fiegel and Steffi Ehlert, in a pub in Ogmore-by-Sea. Mr Russill said, "They were lovely guys to meet. They were really full of life. They had sharp memories. They could remember the hedges they ran to."

But the two veterans at first disagreed about which room in the hut they had dug from. A series of wall paintings resolved the question.

Mr Russill said, "They had a bit of an argument about which room was theirs. One of the guys was very good at drawing. He had drawn a couple of big-breasted women on the walls so the guards would look up and not down at the floor."

Being back at the site of their escape was an emotionally tough experience.

"I think they got a bit tearful when they went back; it was a big deal for them," said Mr Russill.

He returned with a small digging vehicle. They dug 2m down at the point where they had detected the vacuum and found nothing. Mr Russill remembered the frustration.

"It could have been an animal burrow," he said. "I was thinking, 'Oh no ... it's all a false alarm.' Then we did one scoop and the ground slipped a tiny bit. That was it."

An engineer, who was also an experienced caver, was lowered into the tunnel. He declared the 60ft-long passage to be in perfect condition.

A crude ventilation system made from tinned milk cans was still in place.

An expert on POW escapes was impressed with the size of the passage.

Mr Russill said, "It was a luxury tunnel compared to some of the English ones in Germany."

The future of the tunnel and the hut with its drawings is uncertain because of strong lobbying to build a Welsh rugby academy on the site. The approved plans do not affect the hut but calls have been made for it to be bulldozed.

Mr Russill enjoyed the hunt for the tunnel.

He said, "Normally you do surveys to find stuff in the ground but you are seldom around to dig up the ground."

The story of the prison escape remains a vivid part of local folklore.

As soon as the escape was discovered, armed soldiers, the Home Guard, dogs, local children and Girl Guides scoured the area in one of the largest manhunts of the war.

Howard Grossley, a Canadian deserter living in Porthcawl, shot his girlfriend Lily Griffiths and claimed the accident took place while he was trying to shoot at POWs.

Miss Griffiths first agreed with this account but later changed her testimony.

She claimed that Grossley had been about to kill himself and she was shot while grappling for the gun.

After she died from her injuries he was hanged and buried at Cardiff Prison.

The escapees were swiftly captured but the breakout was one of the biggest in the war - second only to the 80 Allied POWs who escaped from Stalag Luft, as portrayed in The Great Escape.

Channel's 4's The Welsh Great Escape, in which the search for the tunnel is featured, will be shown at 9pm on December 30.