http://www.dailymail.co.uk/news/article-2063652/The-classic-Steve-McQueen-movie-immortalised-tunnels-Stalag-Luft-III-PoW-camp--astonished-archaeologists-discovered-fourth.html

I know this story is actually a year and a half old, but I just learned of it today. This is a story near and dear to my heart, as my grandfather was a POW and tunnel rat at Stalag Luft I. I'm going to have to hunt down a copy of "The Great Escape" and watch it again with my son!

I have actually just bought that film.
Also just finished a book where some of the story is told. not many managed to escape .
Two who did managed it, later drowned on the way from Denmark to Sweden, only one of the two bodies where found.

Edit:
Found the story..

J?rgen Thalbitzer was taking of from Portreath, Cornwall, at 15.20 in Spitfire Vb, AB864 (AZ-). He is shot down, but manages to crash land. For some time he is hiding in France, but eventually he is captured. He becomes prisoner of war.

In the 234 Squadron ORB it is described as follows:

The Squadron carried out a low level attack between Plouescat and Guissmey [possibly Guiss?ny, ed.]. Enemy opposition (fighters) were encontered, togehter with light flak and machine gun fire from Landereau. Radio masts, high tension cables, and masts, goods trucks, signal box and water tower were attacked. [3]

Under the presumed name John Thomson, he is imprisoned in Stalag Luft III (Gefangennummer 629), where he joins the team of escapists. As a result he ends up in a punishment camp at Schubin, Poland (Oflag XXIB). [4]
Escapes from captivity, but drowns

In March 1943 J?rgen Thalbitzer is among more than 30 prisoners to escape from the camp. J?rgen is teamed up with Lieutenant Commander Jimmy Buckley of the Fleet Air Arm, who had chaired the Escape Committee at Schubin. The plan is to reach Stettin on foot and to board a Danish vessel. Reaching Stettin they are without luck as there are no Danish vessels. They jump on a freight train for Rostock, but have no more luck here. In the end they board a vessel in Flensburg.

They eventually arrive in Copenhagen where J?rgen leaves Buckley in the ship while he visits his family. On the night between 28 and 29 March 1943 they attempt to cross the Sound between Denmark and Sweden, but they disappear possibly being hit by a larger vessel. The body of Buckley is never found, but the body of J?rgen washes ashore some months later. He is identified by his signet ring.

Source: http://www.danishww2pilots.dk/