When the Territorial Army expanded in the summer of 1939, the 5th Battalion (based around Plymouth) spawned a new battalion, the 7th. Initially each became machine gun battalion in the 43rd Wessex and 45th Wessex Divisions respectively. In the autumn of 1941 both battalions were converted to become anti-tank gunners within the Royal Artillery. The 5th became 86th A/T Regiment while the 7th became the 87th.
The 87th were the first to go to war, landing in North Africa with First Army in February 1943. Equipped with the 6-pounder anti-tank gun, they saw action in the fierce closing battles of the Tunisian campaign around Bou Arada and Medjez el Bab and in the final assault on Tunis. In these battles in March and early April 1943 the British first encountered the formidably armoured and heavy-gunned German Tiger tank. In May 1944, a year after the victory in North Africa, the 87th were disbanded in the Middle East.
The 86th landed in Normandy in late June 1944 and in mid-July, as part of 43rd Wessex Division, fought on Hill 112 and near Maltot. Two of their batteries were equipped with 17-pounder anti-tanks guns while the others were in self-propelled M10 tank destroyers. On Hill 112 two of their troops of M10s knocked out five Tiger tanks and one Mark IV. Their machine guns also downed a Focke-Wulf fighter. Here, on the forward slope, one troop of 17-pounders were overrun by the Germans but the gunners managed to remove their firing mechanisms before extricating themselves in good order. Around Maltot the Regiment lost three M10s knocked out. They then saw action in the Falaise pocket, in the south of Holland and across the Rhine until the war’s end in May 1945.