'Chaffinch' (i) was a British attack by a three-man Norwegian party (T. Stenersen, O. Sandersen and M. Olsen) of the Special Operations Executive on shipping in the harbours of German-occupied Norway (23 January/late May 1943).
Delivered by air, the party was to work in the area to the west of Oslo, establish radio contact, provide instruction and training, prepare a small local team of six men (later supplemented by another three such teams) to carry out assassinations, and investigate the possibility of local groups undertaking shipping sabotage in the area of Oslo and Drammen using the limpet mines which the party had taken with it. After consideration of an attack on shipping in Horten, the men of the party on 19 May attached a limpet mine to the freighter Sanev while she was docked at Moss. The mine’s detonation on the same day sank the ship. A later attempt to attack shipping in Oslo harbour was abandoned, and the party left Norway at the end of May.