This was a British attack by a four-man Norwegian party of the Special Operations Executive, delivered by air, on shipping in Oslo harbour and the northern part of the Oslofjord, and most especially troopships, in German-occupied Norway (11 October 1943 onward).
Working on the basis of intelligence information from agents in Norway, the operation was based on the skills of Max Manus, Gregers Gram, E. Juden and C. Viborg. Early in January 1944 reached arrived in Stockholm in Sweden in an unsuccessful effort to secure permission to develop and use ‘baby’ torpedoes. In February a ‘Bundle’ undertaking sank a German patrol vessel, but from this point on the team took on the additional responsibility of creating and disseminating propaganda under the designation ‘Derby’.
Manus and Gram also began to work with the other SOE teams in the Oslo area, but attacks on shipping were not abandoned and in June 1944 six limpet mines were placed on the 13,882-ton transport Monte Rosa, but their detonations did not cause major damage. In August a German destroyer was attacked using a home-made torpedo, and in January 1945 limpet mines were placed on Donau and Rolandsech, the subsequent detonations damaging both target vessels.