'Rook' was a British operation by the Special Operations Executive which began life as part of a plan, originally called 'Tiger', to kidnap a German naval officer, Kapitän Hans Rudolf Rösing (11 March/May 1945).
Rösing was believed to be the planner of U-boat operations launched from Bergen in German-occupied Norway, but was in fact the Führer der U-boote 'West' between July 1942 and May 1945, and as such responsible for all the U-boats committed to the Battle of the Atlantic, and thus a great majority of the entire U-boat fleet. With the loss of the U-boat bases in France during the autumn of 1944, when the Kriegsmarine was compelled to transfer the remaining U-boats of the 2nd Unterseeboots-Flottille and 7th Unterseeboots-Flottille to bases in Norway, Denmark and northern Germany, and at this time Rösing had his headquarters at Bergen.
Also instructed to organise sabotage and intelligence groups to undertake the work previously carried out by the Saborg communist organisation and BAR, the two-man party of L. Petteresen and C. Tønseth arrived by sea on 11 March but failed to locate its target. The team then worked closely with the district leadership of the Milorg military resistance organisation, and at the beginning of May made contact with the German commander in Bergen. On 8 May the Gestapo left the town and on 9 May around 1,100 local men were mobilised and occupied the area’s most important points.