During the Second World War he served as General Officer Commanding-in-Chief (GOC-in-C) British Troops in Egypt, in which role he launched Operation Compass, attacking Italian forces with considerable success, in December 1940.

Following the end of hostilities, he left Port Natal on the SS Malta in late September 1902, together with other officers and men of the 2nd battalion Rifle Brigade who were transferred to Egypt.

[1] After being promoted to brevet lieutenant colonel on 1 January 1919 and being hand-picked for the first post-war staff course at Camberley, Wilson was given command of a company of cadets at Sandhurst.

[19][17] On 15 June 1939, Wilson was appointed General Officer Commanding (GOC) of the British Troops in Egypt, with the rank of lieutenant-general,[20] in which role he was also responsible for giving military advice for a range of countries from Abyssinia to the Persian Gulf.

O'Connor's HQ, initially designated British 6th Infantry Division, was activated in November and became responsible for the troops at Mersa Matruh.

However, their advance was reversed when on 17 June France sought an armistice and the Italians were able to move their forces from the Tunisian border in the West and reinforce with 4 divisions those that opposed Wilson in the East.

Although the Allied forces were hopelessly inadequate Churchill's War Cabinet had thought it important to provide support for the only country outside the Commonwealth which was resisting the Axis advance.

[28] In October 1941 Wilson took command of the Ninth Army in Syria and Palestine and was appointed to the honorary title of Aide-de-Camp General to the King.

[note 2] In February 1943, after Montgomery's success at Alamein and the expulsion of Axis forces from North Africa, Wilson was appointed Commander-in-Chief of the Middle East.

However, on orders from London to create a diversion during the fighting in Italy, in September 1943 he organised an unsuccessful attempt to occupy the small Greek islands of Kos, Leros and Samos.

[33] Jumbo Wilson was keen to follow through with the deception plan Undercut, when unexpectedly the Germans decided to withdraw from Greece altogether.

[27] One of Wilson's most secret duties was as the British military representative on the Combined Policy Committee which dealt with the development, production and testing of the atom bomb.

[8] In January 1946 he was appointed aide-de-camp to George VI of the United Kingdom and was then created Baron Wilson, of Libya and of Stowlangtoft in the County of Suffolk.

[36] The son, Lieutenant-Colonel Patrick Maitland Wilson, accompanied his father in the Middle East during the Second World War as an intelligence officer.

Never a rich man, when Field Marshal Lord Wilson died on 31 December 1964 in Chilton, Buckinghamshire,[11] his estate was proved at only £2,952 (roughly £100,000 in 2013[37]).