Shortly before the outbreak of the Second World War in September 1939, Morgan was promoted to brigadier and assumed command of the 1st Support Group, part of the 1st Armoured Division, which he led during the Battle of France.

At an early age it was decided that Frederick would become a British Army officer, and in 1907 he entered Clifton College,[4] a school noted for its connections with the Royal Military Academy, Woolwich.

[7] He volunteered for service in India, and in January 1914 departed on the British-India Steam Navigation Company troopship Rewa, joining the 84th Battery, 11th Brigade, Royal Field Artillery, which was stationed in Jabalpur.

[10] On returning to the front, Morgan became aide-de-camp (ADC) to Brigadier General Edward Spencer Hoare-Nairne, the commander of the Lahore Divisional Artillery.

Unlike the later occasion when all men, women and even children smelt the whiff of hell, in 1919 there were few among those whose task had been to keep the home fires burning who could, even with the utmost endeavour, comprehend what had happened to those of us who came back, bent or broken, aged beyond our years.

This was followed in 1925 by a year's secondment to the headquarters of Lieutenant-General Sir Claud Jacob's Northern Command, where Morgan helped plan and direct large-scale manoeuvres.

Morgan's classmates at Quetta from 1927 and 1928 included William Slim, John Crocker, Kenneth Anderson, David Cowan, George Alan Vasey and Tommy Burns.

[2] After graduation, Morgan was posted to the 70th Field Battery at Lucknow,[22] and then was artillery staff officer at headquarters Western Command, under Brigadier Henry Karslake.

When Karslake became major-general, Royal Artillery, at GHQ India in 1931, he brought Morgan to Delhi to serve with him as his General Staff Officer (Grade 2).

[25][1] Returning to England in 1934, Morgan assumed command of the 4th Anti-Aircraft Battery, which was deployed to Malta during the diplomatic crisis that accompanied the Italian invasion of Abyssinia in 1935.

[2] Here he became increasingly disturbed at the lack of urgency that the British government displayed in the face of a war that Morgan and his fellow staff officers felt was inevitable and imminent.

In the course of this very campaign, if one may dignify the disaster thus, I had seen French generals create imaginary "masses of manoeuvre" with strokes of the crayon and dispose of hostile concentrations, that unhappily were on the ground as well as on the map, with sweeps of the eraser.

On 8 August 1939, just a few weeks before the outbreak of the Second World War, Morgan was promoted to the temporary rank of brigadier[29][1] and assumed command of the 1st Support Group of Major-General Roger Evans's 1st Armoured Division.

The division, which moved to North Yorkshire under Northern Command in mid-December, was placed on the Lower Establishment the following month, losing much of its artillery, engineers and divisional troops and receiving a low priority for modern equipment.

In October of that year his headquarters became a mobile formation, was redesignated I Corps and placed under his American superior, Lieutenant General Dwight D. Eisenhower.

[35] Morgan's I Corps headquarters was later designated Force 125 and was given command of Walter Clutterbuck's 1st and John Hawkesworth's 4th Divisions, and the task of dealing with a German thrust through Spain to Gibraltar.

In November and December part of the staff moved to the South Rotunda, a bombproof structure that had originally been fitted up as an anti-invasion base, which was connected to the various ministries by the Whitehall Tunnel.

Missions were also exchanged with General Dwight D. Eisenhower's Allied Force Headquarters (AFHQ) in Algiers to coordinate the plans of offensive action in the Mediterranean and north western Europe in 1944.

In October and November, Morgan went to Washington, to discuss the operation with the Combined Chiefs of Staff,[43] accompanied only by Major-General Nevil Brownjohn and an aide.

Roosevelt turned down Morgan's request for the services of Anthony Joseph Drexel Biddle, Jr. to assist with civil affairs, and also cast doubt on whether Marshall could be spared to become Supreme Allied Commander.

[45] In December 1943, when General Sir Bernard Montgomery, who had just arrived in England after commanding the British Eighth Army on the Italian Front, was appointed C-in-C Land Forces for the invasion, he declared that Morgan's original plans were impracticable;[46] they had originally been limited by the availability of landing craft, but Montgomery insisted it would require more men attacking over a wider front.

Ultimately, more landing craft were obtained and the invasion was scaled up to Montgomery's satisfaction, at the cost of a month's delay and a reduction in the Southern France operation.

However, all the key features of Morgan's plan remained; the choice of Normandy as the assault area, the use of Mulberry harbours, the deployment of American forces on the right and British on the left, the use of airborne troops to cover the flanks, and some form of diversionary operation in Southern France.

Eisenhower brought his chief of staff for AFHQ, Major General Walter Bedell Smith, and moved the headquarters to Bushey Park.

He applied his energy and planning skills to the problem of providing relief to millions of refugees and displaced persons in Europe in the wake of the war.

[60] One reporter quoted Morgan as remarking that "the Jews seem to have organised a plan enabling them to become a world power- a weak force numerically, but one which will have a generating power for getting what they want".

[63] The Board of Deputies of British Jews issued a statement that said that "General Morgan’s references to a “Jewish plot” to become a “world force” coming on top of the Nuremberg evidence of the extermination of nearly 6,000,000 Jews by the Nazis is not only a grotesque bogey, but highly uncharitable and unworthy when it comes from the head of an organization whose purpose it is to bring comfort to suffering victims of Nazi barbarity.

[65] According to the US Holocaust Memorial Museum, "Morgan’s statement also reflected linkages between Jews and “Bolshevism,” while at the same time gesturing toward future Cold War politics.

Indeed, the Nazi regime frequently equated Jewish politics with a communist threat, building on antisemitic stereotypes of the Jews as part of a conspiracy to gain world domination.

The job, the title of which was changed to "Controller Atomic Energy" in 1950, had no written terms of reference, but carried broad responsibility for the coordination of all aspects of nuclear weapons production.