of the Master Spy That Helped Win World War II (1976, 2000)
The British knew that they had to pass what they had learned to America from their atomic bomb research since they didn't have the necessary abilities on their own to take the research further, knowing that Nazi Germany was able to do so. FDR had authorized the Manhattan Project, but the biggest initial threat to the Anglo-American effort to make the atomic bomb was Niels Bohr, who had already split the uranium atom. Two months after Enrico Fermi's successful test of a chain reaction in Chicago, British commandos tried to destroy the Norsk Hydro heavy water plant in Norway. It seemed to the commandos that they had failed in their mission, in that their demolitions didn't make a large noise when detonated, but the truth was they had succeeded. When the heavy water plant went back into production, the Royal Air Force tried to bomb it; the RAF and USAAF air raids inflict any damage, but the guerilla-style commando raid did. Leader in both the US and Britain were too stubborn (or slow) to realize that guerilla strategies/tactics were the way to go at Norsk Hydro.
Underneath Bohr's ever-expanding research laboratory, Danish saboteurs planted explosives "just in case" it was necessary to destroy the lab. Using secret messaging set up by British intelligence, Bohr told the British that he would keep his research going at full-tilt and would not be smuggled to Britain to work. In Denmark, Bohr had immense prestige, and as of yet he didn't know about the Anglo-American effort to build the atomic bomb. Both Bohr and King Christian X of Denmark (age 73) were close, and in the early days of the Nazi occupation in Denmark, both were handled with kid gloves. Christian X was allowed to remain in his castle, believing that his presence would help protect his people, while Bohr blissfully and happily worked in his lab believing he was doing the right thing for science and humanity.
About the only positive concerning Bohr was that he kept up a secret correspondence with a British scientist he respected, and via that pathway Bohr stated that the Germans in the Spring of 1943 were looking for more metallic uranium and heavy water for use in his lab. WS kept up his argument that Britain needed to grab Bohr from the Nazis. WS calculated that when the Nazi occupation of Denmark turned nasty, Bohr would all-of-a-sudden be in the mood to be smuggled to Britain . . . WS didn't wait for that development to occur, and started to organize a plan of escape for Bohr.
Bohr buried his communications with the outside world in his garden as a failsafe to show that he wasn't loyal to the Nazis or a traitor, including his reports on what the Germans wanted and were up to. At last Bohr realized that he had been terribly wrong about the Nazis; by September 1943, orders for Bohr's arrest reached the Gestapo in Denmark. A scientist that Bohr trusted with his theories lost the entrusted documents as he escaped to Sweden, and they were lost forever. Meanwhile, a Nazi reign of terror surged across Denmark as Jews were deported en masse.
With every new revelation about the Nazis, Bohr became more-and-more tortured; finally Bohr reached the conclusion that his giant brain should be in the service of the Allies . . . but how would he reach Britain? Bohr was asked if he would ride in an unarmed bomb bay of a British Moon Squadron aircraft; great secrecy surrounded the Moon flights, in that if the Nazis discovered that the Moon Squadron was flying planes to neutral Sweden the Nazis would almost certainly react violently. The favorite Moon Squadron plane was a modified Mosquito bomber (made mostly of wood, in part to be invisible to German radar) which was designed to carry agents instead of bombs.
A female intelligence agent (related to King George VI of Great Britain) told Bohr of the stark realities of being a secret passenger in the bomb bay; among the problems was that there wasn't much room to move during the flight. In essence Bohr would be helpless and physically cut-off from the pilot until the plane landed, or crashed into the North Sea. If wounded by Luftwaffe fighters, only a small dose of morphine in a first aid kit would be available.
When the pilot tried to communicate with Bohr to check if his oxygen was working, he received no answer. The pilot had to risk flying lower so Bohr could survive, but that meant that Luftwaffe fighters could intercept the plane. The pilot could not turn back to Sweden in that the airfield had already been abandoned, and landing would almost certainly lead to arrest; even if allowed to remain free, the Swedes, under tremendous pressure from Berlin, would never let Bohr out of their sight. The pilot flew full throttle at sea level, trying to reach Scotland which was beyond the reach of Luftwaffe fighters, but it would be a close call in terms of fuel. Ten miles from Scapa Flow, the pilot alerted the British defenses that he was a friend and was getting ready to make his approach; the pilot still hadn't heard from Bohr in the bomb bay.
WS asked a British doctor (who was part of the intelligence network) if there was any chance of Bohr's survival, and the doctor said Bohr's pulse was weak, but that he would pull through. WS quickly made arrangements for Bohr's son, Aage, to be airlifted from Sweden a few days later to join his father, since he was Bohr's right-hand-man in the lab. By the time Aage joined his father, Bohr had recovered from his near-death experience: Bohr's intercom plug had been jerked out of connection at take-off, and he was unable to trace the problem, and unable to hear the pilot tell him to put on his oxygen mask . . . the pilot's decision to fly at a low altitude saved Bohr's life.
Bohr and his son were quickly placed in an office in a drab Westminster hotel and became part of Tube Alloys, the British code name for their atomic research. Bohr was quickly overwhelmed with the knowledge of the other scientists/analysts involved in Tube Alloys, having run solo in Nazi-occupied Denmark . . . it was only then that Bohr truly understood the evil of Nazi Germany . . .