It is one of the great ‘what ifs?’ of World War II. What would have happened had the Nazis acquired a nuclear weapon? The consequences are unthinkable. The sabotaging of the Nazi nuclear programme was therefore one of the most important operations of the war.
Operation Gunnerside, as it was known, the destruction of the heavy water plant in Vemork, Norway, is just one of countless covert operations examined in this book about espionage in the country between 1940 and 1945.
Norway is a vast country with largely inhospitable terrain. Hard enough to occupy, it proved even more challenging to penetrate while under Nazi rule.
Not surprisingly, the first attempt to destroy Vemork, Operation Freshman, ended in calamity, as the Allied planes could not find the appropriate landing sites in the winter weather. Some returned to Britain, but others crashed, with those taken prisoner beaten and killed by the Germans.
Gunnerside, which took place a few months later, was a success. By destroying the Nazi supplies of heavy water, one of the elements regarded as essential for nuclear capability, it brought a definitive end to the weapons programme.
After fleeing from the Nazi invasion in the spring of 1940, the Norwegian government, now exiled in London, wasted no time in beginning a campaign of resistance. Yet their British hosts often froze the Norwegians out of operations they were launching, even if they were to take place in occupied Scandinavia.
Not that the British government was unified in its objectives. The two intelligence agencies, the SIS and SOE, frequently squabbled.
Particularly in the early years, neither the Allies nor the Germans were especially competent. Espionage operations could be astonishingly amateurish, and they could also be disastrous. To this day, the memory lingers of the notorious massacre at Telavåg in 1942, when the Nazis slaughtered an entire village as punishment for harbouring two spies sent from Britain.
Many agents did avoid capture, however. The daring Max Manus is well remembered in Norway, having been immortalised in an excellent 2008 film. My personal favourite is Jan Baalsrud, who escaped German captivity and hid for weeks in the mountainous wilderness, traversing over 170 miles on foot, across water, and on skis, without food or shelter, losing no more than a couple of toes.
Norway had been favoured by Churchill as the site of a potential Allied landing, although France eventually took priority. Bluntly stated, Norway was never essential – the Nazis were even barking up the wrong tree with heavy water, which would not have worked effectively in the development of the bomb.
Yet, as Insall points out, this was not known at the time, and the destruction of Vemork remains an outstanding achievement of the Special Operations Executive. That, and providing the information that led to the sinking of the Tirpitz – another of Churchill’s obsessions – in November 1944.
Insall has used a great deal of new material but expresses frustration at the documents which remain classified. Sometimes less is more, however: there is a bit of information overload, particularly in the early chapters concerning the humdrum process of intelligence gathering and collating. Later chapters, concerning the major operations, are a lot more thrilling, although I recommend Neal Bascomb’s Winter Fortress for an even pacier account of the Vemork sabotage.
Generally, Secret Alliances is a serious account of activity for which, although in the end it was surprisingly peripheral, we can all be grateful. Thanks to men like Manus and Baalsrud, the Nazis were prevented from going nuclear.
Review by Calum Henderson
This is an article from the April/May 2021 issue of Military History Matters. To find out more about the magazine and how to subscribe, click here.