In 1940 Horrocks commanded a battalion during the Battle of France, the first time he served under Bernard Montgomery, the most prominent British commander of the war. Montgomery later identified Horrocks as one of his most able officers, appointing him to corps commands in both North Africa and Europe. In 1943, Horrocks was seriously wounded and took more than a year to recover before returning to command a corps in Europe. It is likely that this period out of action meant he missed out on promotion; his contemporary corps commanders in North Africa, Oliver Leese and Miles Dempsey, went on to command at army level and above. Horrocks' wound continued to impair his health and led to his early retirement from the army after the war.