During the inter-war period, the Canal Brigade had been formed to defend the Suez Canal. After the outbreak of the Second World War, the brigade was redesignated as the 23rd Infantry Brigade on 20 September 1939. It was dispersed in the canal area, and became part of HQ Canal sub-Area troops. In May 1941, the brigade was re-formed to take part in the Syria-Lebanon Campaign, during June and July 1941, as part of 6th Infantry Division. In October 1941, the 6th Infantry Division was re-designated as the 70th Infantry Division. The divisio, including the brigade, and was transported to Tobruk to relieve the 9th Australian Infantry Division. As part of the Tobruk garrison, the brigade helped to fend off Rommel's Axis forces until the siege was relieved at the end of the year during Operation Crusader.