Anyone mildly interested in the second world war probably knows two things about our wartime alliance with Norway, following its invasion by Germany. One is the great Christmas tree that appears in Trafalgar Square every year, a gift from the Norwegian government in recognition of that alliance. The other is the daring raid to sabotage the Norwegian heavy-water plant essential to the German attempt to build an atomic bomb, an operation subsequently filmed as The Heroes of Telemark.
But few are likely to know that the idea of an annual tree gift probably originated with two Norwegians manning one of the many SIS coast-watching stations in occupied Norway from which German shipping was monitored. The men lived for months in a sheepfold, unable to wash or change their clothes. When exfiltrated to Britain, they were introduced to their exiled monarch, King Haakon, who had asked to meet them as they were, and consequently had to hold his nose while talking to them. On their return to intelligence work in Norway, one of them sent the king a Christmas tree. In 1947 the restored Norwegian government made this an annual event.
Nor are many people aware that the successful raid on the heavy-water plant was preceded by a tragically unsuccessful attempt by two gliders carrying British commandos, the first Allied mission in the war to use gliders for landing troops. Weather conditions caused both to crash, killing most on board. Those unfortunate enough to survive were captured and tortured by the Gestapo and then shot, Hitler having ordered that no commandos should be taken prisoner. Of the last two — both already injured — one was strangled with a belt and the other kicked down stairs and shot in the back of the head.
The second, successful, attempt on the plant was made by an SOE team of Norwegian saboteurs who parachuted in to rendezvous with another SOE team, who would guide them to their target. Both teams had to survive atrocious conditions, the first trapped by a five-day snowstorm, the second near starvation after months in hiding and living off reindeer moss soup. The operation was a complete success, disabling the plant for six months, and the attackers uninjured — albeit some had to escape by skiing to the Swedish border 300 miles away. A subsequent attempt to transport the heavy water back to Germany was frustrated by another SOE operation which sank the ship.
There is much, much else in this thorough, authoritative and probably definitive account, which has drawn on unpublished official records, particularly those of SOE, SIS and MI5. Not only does Tony Insall sprinkle his book with memorable operational and human detail — the SOE agent who secretly dosed his mother with laxatives to prevent her boarding a ship he was planning to sink; another who requested that pairs of SIS agents living for months in hides might be issued with boxing gloves so that they could fall out without too much injury — but he never loses focus on the bigger issues. The successes and failures of UK–Norwegian collaboration, of SIS–SOE coordination, of the contribution of both agencies to military and political strategy, of the difficulties of getting timely wartime intelligence out of an occupied country with a hostile climate are all precisely described and fairly assessed.
Even second world war historians have usually underestimated the role of SIS in the sinking of capital ships such as the Scharnhorst, Bismarck and Tirpitz, not to mention numerous lesser ships and, towards the end of the war, submarines. Nor is it widely appreciated how significantly Norwegian operatives of SIS and SOE contributed to the breaking of German secret service ciphers and to Bletchley Park’s ability to read the ciphers of German ships in home waters and U-boats in the Arctic. Their contribution to MI5’s successful interception of 20 German spies smuggled in from Norway is rarely acknowledged; ditto the sabotage operations that helped tie down 365,000 German troops in Norway to the end of the war.
Not everything worked and, as ever in warfare, there was collateral damage and unintended consequences. But overall the effort and sacrifices were undoubtedly worthwhile and, with this clear and comprehensive account, we need no longer be ignorant of them.