Ritchie was the Commander of the British 8th Army when it suffered its major defeat by ROMMEL in 1942. Until mid-1940 Ritchie was Chief of Staff to General BROOKE in Belgium and France and went to the Middle East in 1941 as Deputy Chief of Staff to AUCHINLECK, the Commander in Chief. Ritchie replaced CUNNINGHAM in command of the 8th Army on 26 November 1941 in the middle of the battle for Tobruk. By December Rommel was forced to withdraw to the west of Cyrenaica and the British gained much territory and relieved Tobruk from its ten-month siege. However on 21 January Rommel launched his counterattack with tremendous force and had captured Cyrenaica by 28 January. He now stood at Ritchie’s El Gazala-Bir Hacheim line, a defensive wall of outposts connected by heavily mined strips. Ritchie’s Army was spread over a considerable area with a concentration of force in the north. Rommel concentrated his troops an offensive in the south and attacked on 26 May catching Ritchie offguard Ritchie and Auchinleck now decided to leave a garrison of 35,000 men at Tobruk even though it was indefensible while the rest of the force retreated towards El Alamein. Rommel attacked Tobruk on 20 June and it the next day, with almost the entire on garrison captured and a large cache of supplies falling to Rommel who could now into Egypt within the month. Ritchie was removed from his post on 25 June and replaced by Auchinleck himself.
Ritchie was unlucky to be posted to North Africa in the middle of a difficult situation without any experience in desert warfare facing Rommel. He wenton to command the XII Corps of the British 2nd Army in north-west Europe after D- Day and did this very capably.