In April 1941 the Ansons were replaced with Bristol Blenheims which were deployed on anti-shipping and air-sea rescue duties, as well as night intruder operations over German-occupied Europe. The squadron moved from Detling to RAF Bircham Newton in May that year and converted to Lockheed Hudsons in November 1941. In March 1942, the squadron moved to RAF Stornoway in Scotland, with detachments at Limavady in Northern Ireland for anti-submarine patrols over the Western Approaches. It moved again in at the end of August to RAF St Eval in Cornwall, but this was only a brief stopover before moving to Gibraltar on 5 November 1942 in preparation for the Allied invasion of French North-West Africa.