Europe, 1940. Nazi forces sweep across the continent, with A British invasion likely only weeks away. Never before has a resistance movement been so crucial to the war effort.

In this definitive appraisal of Anglo-Norwegian cooperation in the Second World War, Tony Insall reveals how some of the most striking successes of the Norwegian resistance were the reports produced by the heroic SIS agents living in the country's desolate wilderness. Their coast-watching intelligence highlighted the movements of the German fleet and led to counter-strikes which sank many enemy ships – most notably the Tirpitz in November 1944.

Using previously unpublished archival material from London, Oslo and Moscow, Insall explores how SIS and SOE worked effectively with their Norwegian counterparts to produce some of the most remarkable achievements of the Second World War.