In 1943, General Bernard Montgomery took command of 21st Army Group and requested that Strangeways take charge of R-Force. This was principally a deception force and consisted of armoured vehicles, field engineers and a wireless unit. Strangeways developed Operation "Quicksilver", a significant part of Operation "Fortitude South", with the aim of fooling the Germans that the Allied invasion of Europe would take place at the Pas-de-Calais.