Gunnar Sonsteby: Norway's most decorated war hero

Gunnar Sonsteby, code-named "Kjakan" ("The Chin"), was one of the most prominent members of the Norwegian resistance movement during the Nazi occupation and responsible for countless spectacular sabotage missions and acts of heroism.

A master of disguise, with over 30 identities, he eluded the Gestapo for five years and became Norway's most decorated war hero.

Sonsteby often said that he believed his ability to get away had something to do with how ordinary he looked. It was only towards the end of the war that the Gestapo finally learnt his true identity.

Gunnar Fridtjof Thurmann Sonsteby was born in the small town of Rjukan on 11 January 1918, but his family moved to Oslo in the 1930s. He studied economics and was working as an auditor when Germany invaded on 9 April 1940. In the wake of the invasion, Sonsteby joined the Norwegian resistance in eastern Norway, where he met Max Manus, another significant figure. Initially, their efforts (they published an underground newspaper to fight German propaganda) were modest; but they had the desired effect.

In 1941, Sonsteby was recruited by the secret British military unit the Special Operations Executive (SOE), via its office in Stockholm. He became "Agent 24" in 1942. Following training in Scotland, Sonsteby was parachuted back into Norway. In 1943, he became the contact for all SOE agents in eastern Norway and a key member of the Linge Company, an independent unit of Norwegian commandos under the SOE.

Being high on the Gestapo's "most wanted" list, Sonsteby, a master forger who could replicate the signature of Karl Marthinsen, the notorious quisling leader of the Norwegian Nazi police, perfected dozens of identities which allowed him to slip through German checkpoints undetected. To avoid detection, he moved from flat to flat almost daily. One bolthole was above a bakery. "When I came to that baker's shop I always looked at the girl selling bread. If she gave a special face I would know the Germans were there. I would turn around," recalled Sonsteby.

In the autumn of 1942, Sonsteby was central to the smuggling of Norges Bank's money-printing plates, for the printing of Norwegian kroner, to the Norwegian government in London. Among their many acts of sabotage, the so-called Oslogjengen (Oslo Gang) were responsible for the assassination of several top Wehrmacht commanders and collaborators; the destruction of the Kongsberg arms factory; the theft of 75,000 ration books from German headquarters, preventing the starvation of thousands; and the destruction of sulphuric acid manufacturing facilities west of Oslo.

From the spring of 1944, Sonsteby led the Oslo Gang. They were described by the British historian William Mackenzie as "the best group of saboteurs in Europe". On New Year's Eve 1944, they bombed Victoria Terrasse in Oslo, where the Gestapo had its headquarters. Though it cost the lives of 78 Norwegian civilians, it was viewed as a strike at the heart of the Gestapo's power in Norway.

Crucially, after D-Day, Sonsteby set his sights on the Norwegian railways, preventing German reinforcements moving back to the front line. His team later executed the sinking of the German transport ship Donau outside Drobak in 1945 and the bombing of the Employment Office's archives in Oslo, which prevented the Nazis' planned, forced mobilisation of young Norwegians.

After the liberation of Norway on 8 May 1945, both the British and Norwegian intelligence services tried to recruit Sonsteby, but he refused. "I didn't want any more war. I had had enough. I'd lost five years of my life." Instead, in 1945, he left Norway for America and Harvard Business School. He then worked in the oil industry before returning to Norway to work in private business.

Throughout the post-war years and particularly in retirement, Sonsteby gave lectures to young Norwegians about the Second World War and the need to fight for democratic values. He was also involved in formulating the Norwegian defence and foreign policy, and was known for supporting the Norwegian involvement in Afghanistan.

In 1945, Sonsteby was awarded the British Distinguished Service Order and the US Medal of Freedom with Silver Palm. He remains the only Norwegian to receive the War Cross with Three Swords. In 2008, he became the first non-American awarded the US Special Operations Command Medal. In April, he became the first person to receive the Norwegian Defence Cross of Honour.

Gunnar Sonsteby, resistance fighter: born Rjukan, Norway 11 January 1918; married Anne-Karin; died Oslo 10 May 2012.