The Great Escape is one of our best-loved films.
Most famous for the nail-biting escape sequence in which Hollywood star Steve McQueen - or rather, his stunt double Bud Ekins - tries to leap a barbed wire fence on a Triumph Trophy motorbike.
The real-life story is at least as remarkable as the film.
Today is the 75th anniversary of the escape attempt from Stalag Luft III in 1944.
Its meticulous planning and ingenuity allowed dozens of Allied prisoners-of-war to escape under the noses of the Nazis and is one of the greatest stories to come out of the Second World War.
The 1963 film classic's jaunty theme tune is still whistled today.
Amazingly, bearing in mind what Hollywood usually does to wartime events, even experts praise the movie's realism.
The author Jonathan Vance, who wrote a new edition of The True Story Of The Great Escape, out this week, says the movie is surprisingly true to life.
"I've always been a huge fan of the film," Vance told The Express.
"It's remarkably realistic, particularly in its recreation of the details of camp life."
That said, Vance accepts the character played by McQueen was a total fabrication.
Or, as former RAF PoW Wing Commander Ken Rees puts it: "It's always said that he was based on me, apart from him being a 6ft tall American and me a Welshman of about 4ft 3in who can't ride a motorbike."
McQueen's attempt to jump over a German barbed wire fence on his motorbike remains the film's iconic scene.
But, says Vance, in reality the weather during the escape was terrible.
"McQueen couldn't have jumped his motorcycle if there had been a foot of snow, as there was in March 1944."
The true story of the Great Escape began in 1942 when Stalag Luft III was constructed in eastern Germany - now Poland - as an escape-proof camp for rebellious prisoners-of-war who'd tried breakouts before from other camps.
It was thought the sandy soil would make it near impossible to dig tunnels.
But the next year, three British prisoners used daily exercises on a vaulting horse to cover up their construction of a tunnel as it edged to the perimeter fence.
This scenario became the basis of The Wooden Horse movie of 1950.
It was in early 1944 that RAF Squadron Leader Roger Bushell decided on the mass breakout.
This became the story of The Great Escape, involving over 600 prisoners digging tunnels with some 200 selected to break free.
The prisoners were not just Britons.
This week sees the publication of Escape From Stalag Luft III, the memoirs of Bram "Bob" Vanderstok, a Dutch prisoner who joined the escape team.
Bram's son Robert, who wrote the foreword, explains what made his dad and his comrades so determined to get out.
"All of the men involved in the Stalag Luft III breakout knew the risks involved," says Robert.
"Most would have clearly felt that their role as patriotic servicemen required their continued resistance. Simply sitting out the war was anathema to them."
Three tunnels were constructed, codenamed Tom, Dick and Harry.
The sandy soil was shored up with wooden planks from the prisoners' beds. Digging tools were improvised from tin cans of powdered milk supplied by the Red Cross, and lamps fuelled by fat scooped off the camp's soup.
Improvised pumps brought fresh air into the tunnels. Excavated sand was painstaking scattered round the camp from pouches inside their trousers.
Regular inspections by the Gestapo made it increasingly likely that the escape tunnels would be revealed, so Bushell pushed for the breakout to be earlier than planned.
With Tunnel Harry finished, a moonless night on March 24 was chosen.
But when the first prisoners emerged, the tunnel was just short of the nearby forest, exposing them to the guns of the German guards.
An Allied air raid shut down the tunnel lighting and in the middle of the night it collapsed.
Still, 76 prisoners crawled to freedom before the 77th man was spotted. Pandemonium ensued.
All were caught bar three. One was Bram, who had served in the RAF.
With the help of the resistance, he made it across Europe to a British consul in neutral Spain, then freedom in Gibraltar.
Adolf Hitler was so embarrassed that he ordered all the captured men be shot.
Even some of the Germans argued it was against Geneva conventions, but the SS insisted on executing over half the recaptured prisoners.
The escape leader Roger Bushell was executed alongside 50 others.
After the war many of the SS were caught, tried and hanged or imprisoned.
SS General Arthur Nebe, who oversaw the mass slaughter, was executed for plotting against Hitler in July 1944.
"No one could have imagined or anticipated the Nazi's overresponse in murdering 50 escapers," says Robert Vanderstok.
"The spirit of these men has been endorsed and glorified in numerous tributes, books, movies and reunions.
"This small event has earned a place in military history."
Certainly, The Great Escape is one of the greatest examples of inventiveness, persistence and sheer bloody-mindedness to strike a blow against tyranny.
For that alone it deserves to be remembered for many more years.
The Great Escape
- The purpose-built camp was opened in April 1942 and the Germans considered it to be practically escape-proof.
- Three tunnels were dug...codenamed Tom, Dick and Harry.
- Of the 76 men who escaped, only three got away, two Norwegians and a Dutchman.
- The rest were recaptured and Hitler personally ordered the execution of 50 of the men.
- Bribed German guards provided supplies for the escape.
- The camp was liberated by Soviet forces in 1945.
How to find out more
- Tim Newark is author of Fifty Great War Films (Osprey Publishing, £10).
- The True Story Of The Great Escape is by Jonathan Vance (Greenhill Books, £9.99).
- Escape From Stalag Luft III is by BramVanderstok (Greenhill Books, £25).
- To order, call the Express Bookshop with card details on 01872 562310.
- Alternatively send a cheque or PO payable to The Express Bookshop to PO Box 200, Falmouth, Cornwall TR11 4WJ, with your book choice's name on.
- Or visit www.expressbookshop.com. UK delivery is free
FASCINATING FACTS ? The purpose-built camp was opened in April 1942 and the Germans considered it to be practically escape-proof.