The experience, Adolf Burger would later recall, was like being “corpses on holiday.” Imprisoned in the Sachsenhausen concentration camp north of Berlin, he was detailed to Operation Bernhard, a massive Nazi plot that relied on concentration camp inmates to forge British currency.

The fake bank notes – a total of more than 130 million pounds – were to be dropped by Luftwaffe airplanes over England in an attempt to upset the British economy. Although ultimately aborted, the top-secret plan, unknown at the time even to the camp commandant, is believed to have been one of the largest attempts ever at financial sabotage.

“It was a forgery factory,” said Margaret Shannon, a Washington-based research historian who collaborated on a book about the episode.

Because the scheme depended on the labor and skill of inmates – craftsmen, bankers, at least one professional counterfeiter and book printers such as Burger – the prisoners received some special privileges, such as the provision of blankets, civilian clothing, cigarettes and extra food. But they knew that at any time they might be killed, and it was only amid the chaos as the Allies advanced in 1945 that they escaped execution.

“In a way, it was worse than Auschwitz because we knew for certain they were going to kill us because of what we had done,” Burger later told the Israeli newspaper Haaretz.

Burger, whose account of Operation Bernhard was later dramatized in the Oscar-winning Austrian film “The Counterfeiters,” died Dec. 6 in Prague. He was 99. The Associated Press reported his death, citing an announcement on the public broadcaster Czech Radio. The cause was not immediately available.

Burger was born on Aug. 12, 1917, to a Jewish family in Velka Lomnica, a village in what was then Austria-Hungary and is now northern Slovakia. Trained as a typographer, he did his earliest counterfeiting as a member of the Communist underground, producing false baptism papers in an effort to help Jews survive persecution.

Slovakia, according to the U.S. Holocaust Memorial Museum, was the first Axis partner to permit the deportation of its Jews for the Final Solution. Burger was arrested in 1942, the day before his 25th birthday, and deported with his wife, Gisela, to Auschwitz, where she perished.

“I had two choices: either to go and touch the barbed wire with 1,000 voltage in it and be dead in a second, or stay alive,” Burger later said in a radio interview cited by the AP. “I chose life, so I can tell everyone what they have done here.”

He withered to 80 pounds and was infected with typhus in a Nazi medical experiment, the Wall Street Journal reported in a 2007 profile. He said that a guard took a rifle to his face and knocked out his teeth simply because his given name was, like Hitler’s, Adolf.

But in 1944, Burger was informed that he had been chosen for a special assignment. Ordered by SS chief Heinrich Himmler and named for its SS overseer, Bernhard Krueger, the project involved roughly 140 inmates selected mainly from Auschwitz on the basis of their prewar professional expertise.

They were gathered at Sachsenhausen and housed in two barracks with windows painted over so that their activities could not be observed. Inside, the men churned out millions of bank notes, adhering to the highest standards of quality, as required by the Nazis, but sometimes engaging in delaying tactics to sabotage the effort.

“Britannia was hard” to capture, Burger told the Journal, referring to the depiction in the top-left corner of the bank note of the toga-clad, spear-wielding symbol of Great Britain.

The inmates also forged stamps, passports and U.S. dollars, but the British bank notes accounted for the bulk of their work – a stockpile worth the modern-day equivalent of $7 billion to $10 billion,depending on the exchange rate, according to Shannon, who assisted author Lawrence Malkin on the volume “Krueger’s Men: The Secret Nazi Counterfeit Plot and the Prisoners of Block 19.”

As the Allies closed in, the counterfeit operation was moved to camps in Austria, first Mauthausen and then Ebensee, where cases of the money were thrown into the waters of the Alpine Lake Toplitz.

Germany never managed to deliver the counterfeit money to England because of losses sustained by the Luftwaffe, Shannon said. Some of the bank notes were used to pay German spies and informants; others made their way to fleeing Nazi officials and, after the war, to refugee workers spiriting Jews into Palestine. The counterfeit cash was of such high quality that the Bank of England removed from circulation all notes worth more than 5 pounds for two decades.

Burger settled after the war in Prague, where he reportedly ran a taxi company. He wrote several memoirs, including one translated in English as “The Devil’s Workshop: A Memoir of the Nazi Counterfeiting Operation.”

That volume inspired “The Counterfeiters” (2007), directed by Stefan Ruzowitzky and the recipient of the Academy Award for best foreign-language film. The movie, which took liberties with the historical events, explored the morality of inmates working on behalf of the Nazi war effort.

Responding to the film, Malkin once said that camp inmates had no choice and that it was wrong to suggest that they did. He also urged caution in the reading of Burger’s memoir, which Malkin said was drawn in part from unreliable, postwar East German sources, and which Malkin regards as incomplete because Burger was brought into Operation Bernhard two years after it began.

Burger’s second wife died in the early 2000s. He had three daughters. A complete list of survivors could not be confirmed.

Burger spoke frequently with students about the Holocaust and was interviewed along with other survivors in the book “Taking the Stand: We Have More to Say,” by Bernhard Rammerstorfer.

Burger expressed conflicting emotions about his experiences in the counterfeit operation. In 2007, he told Haaretz, “the important thing was to survive. We didn’t care about the others in the camp. I did not sell my soul and was not a hero. I worked in order to survive.”

But two years later, speaking with the Telegraph, a British newspaper, he said that “of course it was terrible and I think we all felt guilty about it.”

“All I can say is that we never forgot what was happening outside our huts,” he said, “and we knew that one day we were going to be like everybody else.”

(c) 2016, The Washington Post · Emily Langer