“For well over a year, Churchill’s government knew that Berlin would have no bomb, but it let the U.S. work on in the dark.”

By Peter Watson

IN MID-1942, just as the Battle of Midway was raging in the Pacific, British military intelligence received five pieces of highly important information regarding Germany’s strategic war aims. It was intel that had the potential to save tens of thousands of lives and change the very shape of the post-war world.

The first was from a well-placed spy in Berlin. He was Paul Rosbaud, a 46-year-old Austrian scientist and Anglophile who’d had a fondness for the English ever since being held in a British POW camp at the end of World War One.

Between June 4 and 10, Rosbaud was present at an informal rendezvous of the German Physical Society at a restaurant off the fashionable boulevard Kurfurstendamm in central Berlin. The gathering took place just after an official meeting between physicists and the country’s military leaders – generals and admirals and, not least, Albert Speer, Hitler’s Minister of Armaments and War Production.

At the gathering in the Ku’damm café, Rosbaud learned of a momentous decision taken days before by the top leadership in the Third Reich: Germany would not proceed with the development of an atomic bomb, an as of yet un-invented superweapon capable of unprecedented destruction. The advice that Nobel Prize-winner Werner Heisenberg and other scientists had given Speer was that nuclear energy held great promise for the future, but that there was little chance that the technology could be used to produce bombs, at least any that would have an effect on the current war. Germany simply did not have the right equipment (such as cyclotrons) and so the development of nuclear weapons contravened Hitler’s policy of concentrating only on armaments that could be of immediate use. The news was welcomed by the Allies; any threat of Hitler developing the capacity to hold the world to ransom suddenly seemed remote.

Almost as important, Rosbaud revealed that it was the considered opinion of the German scientists that neither the Americans nor the British had the required expertise to manufacture a similar bomb of their own.

Rosbaud lost no time in flying to Oslo – Norway was then occupied by the Nazis – to alert the Norwegian underground, XU. It was one of the ways he sent information to the British.

At almost the same time in London, Reginald Jones, who headed a special outfit tasked with exploring the wartime uses of science and assessing enemy breakthroughs, made yet another discovery. Recent German science journals reaching London via neutral Sweden and Switzerland were suddenly publishing what should have been secret papers on nuclear fission. But, what really drew his attention was the fact that the articles disclosed details about when the research had been conducted and when it had been submitted for publication. The dates showed that the work had been carried out in 1940 or 1941, but not submitted to the journals until between February and April 1942. So the original work had been carried out by the Germans in secret and its publication had been forbidden for nearly two years. But now, for some reason, it was fit to be released. Jones concluded that Berlin must have been pursuing an atomic bomb in the early years of the war but had decided the project was impracticable and so had allowed its scientists to publish freely in order to claim scientific priority for their research.

But open release also suggested to Jones that the Nazis had no fear that the Allies could not profit from publication either. In short, German scientists had discovered nuclear fission and were convinced no one could overtake them.

Jones’s conclusions, which dovetailed exactly with the intelligence provided by Rosbaud, had been obtained independently.

That was not all. Over that same summer similar reports were coming in from Norway by way of German physicists working there. The country was crucial for atomic research because, by chance, it had the only plant in the world capable of producing heavy water on a scale large enough for atomic bomb-making. The facility was located at the Vemork hydro-electric plant. Heavy water, a key ingredient in early atomic research, slows down neutrons, making nuclear fission more likely.

In the summer of 1942, using visits to the plant as cover, three German nuclear physicists – Karl Wirtz, Hans Suess, and Hans Jensen – secretly told the resistance that the Nazis were not working on a bomb.

Of course, these various reports could all have been part of an Axis disinformation campaign, a conspiracy to lull the Allies into a false sense of security. Many in American intelligence thought as much. But the British also had the detailed report from Paul Rosbaud, analysis on which they knew they could rely.

Finally, the British knew from a senior Norwegian at the Vemork Plant and XU mole named Jerome Brun, that by the summer of 1942 the plant’s heavy water shipments were going to just two addresses: the Kaiser Wilhelm Institute for Physics in Berlin-Dahlem and the Schering quinine factory in Leipzig. The fact that the heavy water was going to these locations, at least one of which was purely academic – and not one consolidated facility, confirmed the exploratory and still experimental nature of the German program.

The timing of these events couldn’t have been more momentous for the outcome of the war and the decades to come, had the information been shared between among the western Allies. Sadly, it wasn’t. In summer 1942, the United States had yet to launch its own atomic bomb program, the infamous Manhattan Project. General Leslie Groves would not be appointed until Sept. 17 of that year. Had the British shared what they knew about Germany’s abortive nuclear program with their American allies, Washington might have spared the time, money and resources racing to beat the Germans to an atomic bomb.

The reasons London chose to keep the secret are numerous and controversial. Security services generally resist sharing the sources of their information and in 1942, the Allies had fallen out so far as nuclear research was concerned. It was also the case that some in the British government worried that the news of Germany’s withdrawal from the race to a bomb might sap the resolve of Allied atomic research. Many in London had convinced themselves that the Allies must have a bomb whatever the Germans were doing.

Throughout the following year the British accumulated no further intelligence that the Nazis were pursuing a bomb. Yet decoded German Enigma intercepts revealed details about the V-1 and V-2 rockets, new submarines, four-engine bombers like the Me 264 and the He 277, and jet or rocket powered warplanes. Compared to this, the absence of any information about atomic matters was starkly revealing.

But surprisingly, the British still did not share any of this with the Americans, who continued to fear that Germany might be as much as a year ahead of them on a nuclear weapon. For well over a year, Churchill’s government knew that Berlin would have no bomb, but it let Washington work on in the dark. By the time the U.S. learned the news, at the very end of 1943, the Manhattan Project too far along – there was no turning back.

To be sure, United States intelligence was little better at sharing facts than its British allies. American authorities had known as early as 1941 that Soviet spies had penetrated U.S. atomic research, that Moscow knew about the plans for Los Alamos, the existence of Oak Ridge and the crucial role of plutonium. Roosevelt was briefed, although not until May of 1943; yet Churchill was never informed. This was important because the British prime minister was adamantly opposed to sharing anything about the bomb with the communists. Had he known early on that Stalin was already aware of what the western Allies were up to, he may well have changed his tune. He might have agreed to cooperate with the Soviets before the first bomb was dropped, defusing tensions with Moscow and possibly even changing the course of the Cold War.

Certainly, this is a story that takes place against the backdrop of an entire world war. For governments on all sides, it’s likely that right hand often didn’t know what the left was doing. Much of the breakdown in communications could also be attributed to the demands of leadership, human frailty and the fog of war. Nonetheless, from the latest evidence we now have, we can conclude that, with different personnel in certain key positions, and if the western Allies had shared what atomic intelligence they had, both sides may well have decided that there was no need to build the atomic bombs and by extension no need to bomb Hiroshima and Nagasaki.

Peter Watson is a historian, journalist and the author of Fallout: How the World Stumbled Into the Nuclear Shadow. His other books include: Convergence; Ideas: A History; The Age of Atheists; The German Genius; The Medici Conspiracy; and The Great Divide. He has written for The Sunday Times, The New York Times, the Observer, and the Spectator. He lives in London.