 Before the war, the 5th Battalion, King's Own transferred from 164th (North Lancashire) Infantry Brigade, 55th (West Lancashire) Infantry Division to 126th (East Lancashire) Infantry Brigade, 42nd (East Lancashire) Infantry Division.The battalion, under the command of Lieutenant Colonel Hayman Hayman-Joyce, mobilised with the rest of the 42nd Division and served with the British Expeditionary Force in the battles of France and Belgium in 1940.When the division was converted to armour, becoming the 42nd Armoured Division, in October 1941, 5th Battalion was transferred to the Royal Armoured Corps and became the 107th Regiment Royal Armoured Corps.