In August 1940, the AA battalions of the Royal Engineers were transferred to the Royal Artillery (RA) and the battalion became 40th (Sherwood Foresters) Searchlight Regiment, RA, serving through the Battle of Britain and The Blitz. In June 1943, it was converted again, becoming the 149th (Sherwood Foresters) Light Anti-Aircraft Regiment, RA and transferred to the 55th (West Lancashire) Infantry Division in Home Forces before joining British Second Army for the Allied invasion of Europe Operation Overlord. The regiment landed in August 1944 and served through the , particularly at the Allied Siege of Dunkirk and the Rhine crossing (Operation Plunder).