Amid all the testimonies about Auschwitz and the Final Solution which have been published since the end of the Second World War, one small group has remained silent.

Alongside the main Auschwitz complex was a prisoner-of-war camp known as Auschwitz E715, where the inmates included several hundred British soldiers.

They have not talked about their experience until now, partly because they were traumatised by what happened to them in the camp, partly because they thought that no-one would be interested, but mainly because few people were aware of their existence.

Indeed, when journalist and author Duncan Little stumbled across the story of the British prisoners of war who worked as slave labourers alongside Jewish Auschwitz inmates at the IG Farben chemicals factory next to the camp, he was shocked. He recalls: “I was at the national archives researching a television programme I was directing and I stumbled across a document about a British man who had been flogged. I wasn’t aware of any British prisoners at Auschwitz.

“I began to do some more picking and I realised there were many British POWs there.” Little made contact with three of those who experienced the horror of the death camp: Brian Bishop, Doug Bond and Arthur Gifford-England. Through their experiences, and archive documents he unearthed, Little put together a book, Allies in Auschwitz, which tells their remarkable story.

But why were British prisoners taken to a place whose existence the Nazis wanted to keep top secret?

“I have struggled to answer that question,” says Little. “It is strange that the Nazis would allow POWs to witness what they were doing. But if you look at the history of Auschwitz, it’s not so surprising. It was built haphazardly and was not initially intended to be a death camp but rather a facility for Russian prisoners of war. It developed into a concentration camp and from there into an extermination camp. It was all fairly ad hoc.”

The regime of the POWs at Auschwitz was not significantly different from those elsewhere. They received Red Cross parcels and, nominally at least, had the protection of the Geneva Convention, but they had to endure the freezing temperatures of the Polish winter and witnessed the extraordinary suffering of the Jewish inmates.

Little Says: “The documents clearly show that Jewish inmates were beaten and killed at the IG Farben factory — the British prisoners witnessed that. They saw people being hanged and they smelled the smoke pouring out of the crematorium a couple of miles away. One British prisoner complained about being forced to work for the German war effort at the factory, at which one of the managers pointed his revolver and said: ‘This is my Geneva Convention’.”

In fact, the British were not immune to Nazi brutality. One soldier, a Corporal Reynolds, refused to climb girders because it was cold and he did not have appropriate clothing — he was shot dead on the spot. There was retribution against other British personnel too.

However, in the midst of the killing there were activities laid on for the POWs which would be familiar to anyone who has seen The Great Escape — there were even organised games of football. But like Jewish inmates, the British prisoners also went on the so-called death march of January 1945, when the camp was evacuated in the face of advancing Soviet forces.

Little says: “The POWs followed the same route taken by the Jewish prisoners a week to 10 days earlier, which meant that along the way the soldiers saw the dead bodies of many thousands of Jews. They were marching in freezing conditions with very little food. They had to use their own resources to find things to eat. Ultimately, the horse which carried their rations in a cart was slaughtered and eaten.”

In the end, the POWs were abandoned by their German guards and liberated by the Americans.

Little feels that the testimony of the British troops is important — particularly in countering Holocaust denial. He says: “They were independent witnesses. It’s an important corroboration of the Holocaust.”

‘Allies in Auschwitz’ is published by Clairview Books at £7.99