On 17 June 1940, the headquarters of the British 6th Infantry Division was designated as the Western Desert Force.

In September 1940, at the time of the Italian invasion of Egypt, the Western Desert Force consisted of roughly 36,000 soldiers and about 65 tanks.

[2] From early December 1940 to February 1941, during Operation Compass, the exploits of the Western Desert Force earned a parody of British Prime Minister Winston Churchill's famous quote, "Never has so much been owed by so many, to so few."

After the Italian forces in North Africa had been reinforced with the Africa Korps under Erwin Rommel during Operation Sonnenblume, Lieutenant General Philip Neame, General Officer Commanding (GOC) Cyrenaica,[5] was captured during Rommel's advance and the Western Desert Force HQ was reactivated[6] on 14 April, under Major-General Noel Beresford-Peirse, to take command of British Commonwealth forces in the western desert and halt the Axis advance at the Egypt–Libya border.

During this reorganisation the Western Desert Force was once again redesignated as XIII Corps in October 1941 and became part of the new army.