During early 1940, Swordfish aircraft of 812 Squadron under the operational command of RAF Coastal Command commenced an aerial campaign against continental enemy-held ports along the English Channel. The aircraft were routinely sortied to deploy naval mines near such harbours, a task that was most challenging due to the limitations of the aircraft and the precision navigation skill involved. To attain the range often necessary to reach some naval facilities, additional fuel tanks were installed in the crew area and the third crew member was left behind. RAF fighters often supported these activities, providing a degree of aerial cover where possible and occasionally conducting counterattacks upon enemy air bases.