Egypt (1939–1941)

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. He made his HQ in Cairo and undertook successful negotiations with the Egyptian government at their summer quarters in Alexandria. The Treaty of 1936 called for the Egyptian army to fight under British command in the event of war and to supplement the limited force then at his disposal – an armoured division then being formed (later to be the 7th Armoured Division) and eight British battalions. He concentrated his defensive forces at Mersa Matruh some 100 miles from the border with Libya.^[21]

Early in August, Sir Archibald Wavell was appointed Commander-in-Chief of the Middle East Command, and he sent reinforcements which had been sought by Wilson, initially the 4th Indian Infantry Division and advanced elements of 6th Australian Division^[22] and, as the buildup at Mersa Matruh continued, Richard O'Connor and his staff at 7th Infantry Division in Palestine were moved to Egypt to reinforce Wilson's command structure there. O'Connor's HQ, initially designated British 6th Infantry Division, was activated in November and became responsible for the troops at Mersa Matruh. It was redesignated Western Desert Force in June 1940.^[23]

On 10 June 1940, Italian dictator Benito Mussolini declared war. Immediately Wilson's forces invaded Libya. 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. The Italian forces invaded Egypt in September 1940, and advanced some 60 miles (97 km) to occupy Sidi Barrani. Wilson was facing very superior forces. He had 31,000 troops to the Italians' 80,000, 120 tanks against 275, and 120 artillery pieces against 250. He realised that the situation was one where the traditional text books would not provide a solution. As with other 1940s commanders he had been well-schooled in strategy, and in thorough secrecy; he planned to disrupt the advance of the superior forces by attacking their extended lines at the right spots. After a conference with Anthony Eden and Wavell in October and rejecting Wavell's suggestion for a two-pronged attack, Wilson launched Operation Compass on 7 December 1940. The strategy was outstandingly successful and very quickly the Italian forces were cut in half.^[24]

Lieutenant-General Sir Henry Maitland Wilson, Commander in Chief Cyrenaica, inspects men of the captured Tripolitanian Camel Corps, Libya.

While Operation Compass continued successfully in 1941 and resulted in the complete defeat of the Italian Army in North Africa, Wilson, who was already highly regarded by his First World War regimental colleague and now Secretary of State for War, Anthony Eden, had also won the confidence of Churchill himself. In a broadcast Churchill said, "General Wilson, who actually commands the Army of the Nile, was reputed to be one of our finest tacticians, and few will now deny him that quality."^[25]

Wilson was recalled to Cairo in February 1941 where he was offered and accepted the position of Military Governor of Cyrenaica.^[17]

Greece (April 1941)

Wilson was appointed to lead a Commonwealth expeditionary force ("W Force") of two infantry divisions and an armoured brigade to help Greece resist Italy and the subsequent German invasion in April 1941. 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. Wilson completed the evacuation of British troops from Greece on 29 April 1941.^[17] He was appointed a GBE on 4 March 1941^[3] and promoted to full general on 31 May 1941.^[26]

Syria, Iraq and Palestine (1941–1943)

A convalescent Winston Churchill meets the outgoing and incoming Supreme Commanders in the Mediterranean, Dwight D. Eisenhower, to Churchill's right, and Henry Maitland Wilson, to his left. Behind them stand (from left to right), John Whiteley, Air Marshal Arthur Tedder, Brigadier G. S. Thompson, Admiral Sir John Cunningham, unknown, Sir Harold Alexander, Captain M. L. Power, Humfrey Gale, Leslie Hollis, and Eisenhower's chief of staff, Walter Bedell Smith.

In May 1941, on his return from Greece, Wilson was appointed GOC British Forces in Palestine and Trans-Jordan and oversaw the successful Syria-Lebanon campaign, in which predominantly Australian, British, Indian, and Free French forces overcame Vichy French forces in fierce fighting.^[27] In July 1941 Churchill recommended Wilson to take command of the Western Desert Force to lead it in its upcoming offensive operation against the Afrika Korps, what would become Operation Crusader of November 1941, but General Sir Claude Auchinleck preferred instead Lieutenant-General Sir Alan Cunningham.^[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.^[29]

Wilson enjoyed the confidence of Winston Churchill^[30] and he was Churchill's choice to succeed Auchinleck as commander of the Eighth Army in August 1942; however at the urging of the Chief of the Imperial General Staff, General Sir Alan Brooke, General Sir Bernard Montgomery was appointed to the post. Instead, Wilson was appointed to command the newly created independent Persia and Iraq Command on 21 August 1942.^[31] This command, which had been part of Middle East Command, was created when it appeared that Germany, following successes in southern Russia, might invade Persia (Iran).^{[note 2]}

C-in-C Middle East (1943)

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.^[27] The Middle East was by this time comparatively removed from the main centres of fighting. 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. The British forces suffered large losses to German air attacks and subsequent landings.^[27]

Supreme Allied Commander Mediterranean (1944)

Wilson with Lieutenant-General Sir Oliver Leese, Italy, 30 April 1944

Wilson succeeded Dwight D. "Ike" Eisenhower at Allied Forces Headquarters (AFHQ) as the Supreme Allied Commander in the Mediterranean on 8 January 1944 based at Algiers.^[27] As such he exercised strategic control over the campaign in Italy. He strongly advocated the invasion of Germany via the Danube plain, but this did not take place when the armies in Italy were weakened to support other theatres of war.^[33] Jumbo Wilson was keen to follow through with the deception plan Undercut, when unexpectedly the Germans decided to withdraw from Greece altogether. Although advised by Dudley Clarke that it might backfire and was unnecessary, Wilson was aware of the strategic complexities of the political situation. Every plan the General Staff had a shadow, integrated by 1944 with the American allies at all strategy levels; even to employ an actor imitating Monty arrive at Jumbo's HQ in Algiers.^{[note 3]}

Washington Mission (1945–1947)

Secretary of War, Henry L. Stimson (centre) with Field Marshals Sir Harold Alexander (left) and Sir Henry Maitland Wilson (right)

In December 1944, following the death of Field Marshal Sir John Dill, Wilson was relieved as Supreme Commander, promoted to field marshal on 29 December 1944,^[34] and sent to Washington to be Chief of the British Joint Staff Mission, a post he took up in January 1945.^[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.^[27] Wilson continued to serve as head of the British Joint Staff Mission until 1947, to the satisfaction of Britain and the United States. President Truman awarded him the Distinguished Service Medal in November 1945.^[8]