A memorial has been unveiled at the site of a Nazi concentration camp in Bavaria to 15 agents of Special Operations Executive, the British secret organisation formed in 1940 to “set Europe ablaze”.

The men belonged to SOE’s F Section, responsible for fomenting resistance and carrying out sabotage in Nazi-occupied France. Nine were British, four were French, one was American and one was Canadian. Captured in different places at different times, they were brought together in Flossenbürg Concentration Camp in April 1944.

“These men had a few important things in common,” said Brigadier Tom Paine, of the British Embassy, Berlin, who unveiled the memorial. “All of them had been sent into occupied France on various missions – some more than once. They undertook their missions willingly, knowing that they risked death, because each of them for his own reasons wanted to play a part in liberating France from the Nazi occupiers.”

In Flossenbürg they were held for months in solitary confinement. They were starved and some were beaten. Finally all were executed without trial. Two were shot in 1944. The remaining 13 were hanged, one by one, on March 29, 1945, less than six weeks before the end of the war. In accordance with Nazi efforts to ensure that their fates should never be known, their bodies were cremated.

One officer commemorated is Lieutenant David Sibree, who parachuted into France in 1943. He was captured with four SOE colleagues, Lieutenants Demand, Amphlett and Soskice and Sergeant Harry Graham, after successfully sabotaging a factory at Le Creusot. All five died in Flossenbürg. “I am glad David is being remembered,” said his cousin, Roger Wood. “He was evidently ready to take the difficult path whenever it seemed to him appropriate, whatever the consequence.”

“I hope people will see this memorial and think about the sacrifices made,” said Loulou Troup, niece of Flight Lieutenant Jack Agazarian. “I feel it is not just a tribute to my brave uncle and his comrades but a tribute to everyone who during the war made the ultimate sacrifice.

“This memorial should serve as something which I hope will also help today’s youngsters to fully realise what people like my uncle did for them.”

Flight Lieutenant Agazarian, a British officer of Armenian descent, fell into German hands when, on his second mission, he was sent to an address in Paris and found the Gestapo waiting for him. After six months in Fresnes prison he was sent to Flossenbürg. His final words have gone down in SOE history. Moments before he was executed he tapped in Morse to a neighbouring cell: “Looks like my turn now chaps. Cheerio, and love to my wife.”

The unveiling of the SOE memorial coincided with the formal opening of a new museum documenting the history of the camp. More than 100,000 men and women were sent to Flossenbürg between 1938 and 1945. Most came from the occupied countries of Central and Eastern Europe. More than 30,000 died. Guests who attended the museum’s opening ceremony included 80 survivors and the President of Ukraine, Viktor Yushchenko, whose father was imprisoned in the camp.