'Wagtail' was a British operation by the Special Operations Executive with the original objective of sending a four-man party ('Johnny' Pevik, K. Brodtkorp Danielsen, Ole Halvorsen and Frederick Brekke) overland from Stockholm in neutral Sweden to reconnoitre the railway in the Namdalen, in the area to the north of Trondheim in German-occupied Norway, with a view to cutting off the town at some future date (September 1943).

Before this was undertaken, however, both Pevik and Brodtkorp-Danielsen, along with Halvorsen (team leader and a member of the Norwegian communist party) and Brekke, were instructed to attempt an assassination of the Norwegian informer Henry Rinnan, and the attempt was made on 7 October but failed. The Gestapo then arrested Brekke, which led to the arrest of Pevik, who had by then moved on to start the work in the Namdalen. Pevik was eventually executed in Trondheim.