Among the riches, however, there are no more inspirational or poignant exhibits than those donated by Roberto Gesta de Melo, the IAAF's Brazilian area representative who has his own athletics museum in the middle of an Amazonian forest.

Spikes worn by Alberto Juantorena at the 1976 Olympics when he won 400m and 800m gold

De Melo's contributions commemorate one of the most extraordinary manifestations of the Olympic spirit – the unofficial Games held in German prisoner of war camps in 1944.

The 1944 Olympics should have been held in London. Britain's capital defeated Rome, Detroit, Lausanne, Athens, Budapest, Helsinki and Montreal on the first ballot to earn that honour at the 38th International Olympic Committee (IOC) session.

But something came up.

Despite a raging world war, the IOC organised numerous events at its base in Switzerland to mark the 50th anniversary of its foundation. Between July 23 and August 15, however, another celebration took place which was even closer to the essential spirit of the Games – an unofficial "Olympics" organised in two German prisoner of war camps by a group of determined Polish officers.

These men, captive in the Gross Born and Woldenberg Offlag II-C POW camps, rallied around an Olympic flag made with a bed sheet and pieces of coloured scarves – an effective emblem of the Olympic spirit.

A programme from the Woldenberg camp Olympic Games

The Woldenberg camp, in what is now western Poland, had about 7,000 prisoners, more than 6,000 of them Polish officers, spread out in more than 50 barracks. The camp had a local post service administrated by the prisoners, responsible for the issue of stamps and related material.

The Gross Born camp had about 3,000 prisoners, most of them Polish officers, and held its "Olympics" on July 30 – August 15. The Gross Born Games were preceded by those at Woldenberg, held on July 23-30, which were merely one manifestation of the intense cultural and intellectual activity within the camp.

Many of those imprisoned in Woldenberg were professors or teachers in civilian life, and classes were given in philosophy, law and mathematics. A number of the officers were able to complete full university courses which were recognised after the war. Two professional directors put on theatre productions, and new plays were written. There was also a symphony orchestra.

The cultural life was not enough to persuade the camp inhabitants to stay put, however. At Woldenberg there were several escape attempts. Early in 1942, three officers got away after hiding in empty boxes after unloading food supplies. On Christmas Eve, 1942, three more officers cut through the wire and escaped after a diversionary "fight" outside one of the prisoners' huts occupied the attention of guards and searchlights.

The Woldenberg Offlag II-C POW Olympics were held on July 23-30

But plans for a mass breakout were frustrated in 1943 when a tunnel was discovered as it was within a few feet of being dug to its end.

The "POW Olympics" of 1944 had been preceded by a similar version to mark the "1940 Olympics" – which had been officially destined for Tokyo. However, these "Olympics" – which took place at the Stalag XIII-A camp in Langwasser, near Nuremburg, had to take place secretly as they were not officially recognised by the German captors and their discovery by the camp commanders would have precipitated heavy punishment.

Writing in the Olympic Review (Volume XXVI No 8 April-May 1996), Iwona Grys, director of the Museum of Sports and Tourism in Warsaw, said the flags made for the 1940 and 1944 "POW Olympics" are two of the most prized exhibits within a collection of more than 42,000 pieces.

Grys described how the 1940 flag had been smuggled out of the camp eventually along with other souvenirs of the "Games" – a miniature poster, a paper medal and a volume of poetry – by one of the participants, Teodor Niewiadomski.

The 1940 flag, with which the Olympic oath was sworn, was made out of a Polish prisoner's shirt, which had crayoned onto it the Olympic rings and banners for Belgium, France, Britain, Norway, Poland, Russia and Yugoslavia, symbolising the nationalities of the competing athletes.

The words of the pledge were: "In the name of all the sportsmen whose stadiums are fenced with barbed wire...let these "Jeux Olympiques des Prisonniers de Guerre" be a symbol of the twelfth Olympic Games.

"I declare that the International Prisoner-of-War Olympic Games of the year one thousand nine hundred and forty in Stalag XIII-A at the suburbs of Nuremburg, Langwasser, are open."

The POW Games feature in the 1980 film Olimpiada 40

These Games, and Niewiadomski's story, feature in a film entitled Olimpiada 40 produced and directed by Andrzej Kotkowski in 1980.

According to Grys' account, the 1944 POW Games had a sporting programme that included football, handball, volleyball and basketball tournaments, as well as athletics competitions, boxing and chess tournaments.

The number of competitions – 464 – exceeded the number of participants – 369 – and many officers had to double up over events. The boxing tournament had to be abandoned, as it proved too exhausting and dangerous for prisoners living in the sparse camp conditions. Several contestants had to withdraw after the first round with acute injuries or bone fractures.

The IAAF exhibition will feature numerous items connected with this sporting interlude, including proofs of the Woldenberg Olympic stamps, a postcard with special Woldenberg camp Olympic cancellation sent from Barrack 1 b to 23 a, the Olympic stamp with Olympic cancellation on an admission ticket, required to enter the grandstands, a postcard with a special cachet engraved on, depicting victorious athlete holding a torch, surrounded by olive branch.

Items from the Gross Born camp Games include three Olympic stamps specially issued by the camp's Post Office, two postcards depicting the 10 fen Olympic stamp, bearing the postal publicity Olympic cachet, a cancelled envelope with the three Olympic stamps and the Olympic cachet posted to Block I-54-3, and a medal awarded to one of winners of the Gross Born Olympic Games.

During 1944 in two POW´s camps the prisioners celebrated an “Olympics” called International Prisoner of War Olympic Games

As in the ancient Games, the 1944 "Games" included wider cultural elements – something of a strong suit at Woldenberg anyway. Art, painting, sculpture and music events also took place under the overall management of Lieutenant Antoni Grzesik.

Grzesik had commanded the company in which Janusz Kusocinski, the Olympic 10,000 metres gold medallist at the 1932 Los Angeles Games, had fought in September 1939 in the Battle of Warsaw. And it was Grzesik who donated the 1944 flag to the Warsaw museum thirty years later.

And so the flags remain as a moving symbol of an ideal. One Woldenberg prisoner wrote of their Olympic flag: "It seemed to us, who were removed from the war game that was being waged for life and death, that it would be good if somebody, somewhere – even in the prison camp – remembered this banner, which has always been a symbol of struggle, though never stained with blood."

The majority of those who celebrated their own Games in the Gross Born and Woldenberg camps were dead within a year.

On January 25, 1945, the Woldenberg prisoners were obliged to evacuate the camp as the Allies closed in and force-marched for more than 600 miles. Only around 300 prisoners were liberated by the American Army in Murnau on April 29, 1945. The Gross Born prisoners suffered a similar fate after being marched out of their camp on January 28, 1945 and forced to travel more than 400 miles to Sandbostel. Many of them, weakened by years of captivity, also perished on the journey.

It was a tragic end for the POW Olympians. Their endeavour, however, is deathless.

Mike Rowbottom, one of Britain's most talented sportswriters, has covered the past five Summer and four Winter Olympics for The Independent. Previously he has worked for the Daily Mail, The Times, The Observer, the Sunday Correspondent and The Guardian. He is now chief feature writer for insidethegames.