The Cornwall Fortress Royal Engineers, was a volunteer unit of Britain's Royal Engineers formed in 1908. It helped to defend the coastal towns of Cornwall and sent engineer units to work on the Western Front. Converted to an air defence role before World War I, it served as a searchlight unit during the Battle of Britain, the Blitz, then, as a light anti-aircraft gun unit, it served in the most heavily attacked part of the South Coast of England throughout 1942–44, including the V-1 flying bomb campaign.

The 1st Devonshire Engineer Volunteer Corps, later the Devonshire Fortress Royal Engineers, was a volunteer unit of Britain's Royal Engineers whose history dated back to 1862. The unit helped to defend the vital naval base of Plymouth, and supplied detachments for service in the field in both World Wars. During the North African campaign in the Second World War, the unit's sappers distinguished themselves in bridging the Nile and clearing minefields during and after the Second Battle of El Alamein. Their successors served on the postwar Territorial Army until 1969.