Operation Claymore was the codename for a British Commandos raid on the Lofoten Islands in Norway during the Second World War. The Lofoten Islands were an important centre for the production of fish oil and glycerine, used in the German war industry. The landings were carried out on 4 March 1941, by the men of No. 3 Commando, No. 4 Commando, a Royal Engineers Section and 52 men from the Royal Norwegian Navy. Supported by the 6th Destroyer Flotilla and two troop transports of the Royal Navy, the force made an unopposed landing and generally continued to meet no opposition. The original plan was to avoid contact with German forces and inflict the maximum of damage to German-controlled industry. They achieved their objective of destroying fish oil factories and some 3,600 tonnes (800,000 imperial gallons) of oil and glycerine.
Through naval gunfire and demolition parties, 18,000 tons of shipping were sunk. Perhaps the most significant outcome of the raid, however, was the capture of a set of rotor wheels for an Enigma cypher machine and its code books from the German armed trawler Krebs. This enabled German naval codes to be read at Bletchley Park, providing the intelligence needed to allow Allied convoys to avoid U-boat concentrations. The British experienced only one accidental injury; an officer injuring himself with his own revolver; and returned with some 228 German prisoners, 314 loyal Norwegian volunteers and a number of Quisling regime collaborators.
In the aftermath, the evaluation of the operation differed, with the British, especially Winston Churchill and the Special Operations Executive, deeming it a success. In the eyes of the British the main value of such actions was to tie up large German forces on occupation duties in Norway. Martin Linge and the other Norwegians involved were more doubtful of the value of such raids against the Norwegian coast, but were not made aware of the value of the seized cryptographic information. Following Operation Claymore the Norwegian special operations unit Norwegian Independent Company 1 was established for operations in Norway.