During the Second World War the British Army deployed armoured divisions and independent armoured and tank brigades.
Background During the interwar period, the British Army examined the lessons of the First World War; a need was seen for experimentation with and development of theories of manoeuvre and armoured warfare, as well as the creation of the short-lived Experimental Mechanized Force. The long-term impact was for the army to move towards mechanisation, to enhance battlefield mobility. By the 1930s, the army had established three types of divisions: the infantry division, the mobile division (later called an armoured division), and the motor division (a motorised infantry division). The primary role of the infantry division was to penetrate the enemy's defensive line, with the support of infantry tanks. Any gap created would then be exploited by mobile divisions, and the territory thus captured would be secured by the fast-moving motor divisions. These tactics would transform the attack into a break-through, while maintaining mobility. The country's first armoured division, the Mobile Division, was created in October 1937.
In the 1930s, tensions increased between Germany and the United Kingdom. During 1937 and 1938, German demands for the annexation of the Sudetenland in Czechoslovakia led to an international crisis. This was resolved in September 1938 by the Munich Agreement, which allowed for German annexation of Sudetenland. The Mobile Division (Egypt) was formed.Carter, p. 11 Tensions did not subside, and the British government debated how best to prepare the army for war. In January 1939, the Secretary of State for War Leslie Hore-Belisha proposed splitting the Mobile Division into two smaller formations but found no support for this move. The issue was broached again a month later, and was accepted in principle by the cabinet. Shortly after, France was informed of a preliminary timetable for the arrival of the British Expeditionary Force (BEF) in the event of war: "One Regular Armoured Division will become available about the middle of 1940, the second would not be available 'till a later date. The formation of a second division within the United Kingdom was complicated by the slow pace of British tank production. Several independent Army Tank Brigades were also raised prior to the outbreak of the war, to be commanded by corps. In line with the established doctrine, they would be allocated to support infantry divisions as the need arose.
British doctrine defined light tanks as reconnaissance vehicles armed only with machine guns. Cruiser tanks were swift moving, more heavily armoured, and equipped with a machine gun and an anti-tank gun. The primary role of the cruiser tank was to engage and destroy opposing armoured forces. Its main weapon, a 2-pounder anti-tank gun, was only supplied with armour-piercing rounds. This meant that cruiser tanks were ineffective against entrenched infantry, or in suppressing hostile artillery. Infantry tanks, slower moving and more heavily armoured, were intended to be solely used within tank brigades to support infantry formations.
Armoured divisions
Formation
At the start of the Second World War, in September 1939, the British Army possessed two armoured divisions; one in Britain and a second in Egypt. On 15 December 1939, the 2nd Armoured Division was established in Britain. Despite being formed, it had no fighting sub-units until the following month, when an independent armoured brigade and elements of the 1st Armoured Division were transferred to it. The 3rd Armoured Division also began to form and several armoured regiments were earmarked to join it. Early war tank production went to formations in France or in Egypt resulting in little availability at home. With the British Army defeated in France and evacuated from Dunkirk, these units were equipped with a motley of armoured cars (improvised and factory built) and assigned to an armoured car brigade called a Motor Machine Gun brigade.
Following the Allied defeat during the Battle of France, in 1940, new tank production orders were placed. The Army recognised that German armoured success during the fighting had come about as a result of the concentration of tanks in divisions. The Army intended to raise another seven armoured divisions by mid 1941. This resulted in the 6th, the 8th, and the 9th Armoured Divisions being formed over the final months of 1940. This was followed in 1941 by the 11th and the Guards Armoured Division. These new divisions were supplemented by the 42nd (East Lancashire) Infantry Division being converted into the 42nd Armoured Division. In Palestine, the 1st Cavalry Division was reorganised as an armoured formation and renamed the 10th Armoured Division. Another armoured division, beyond the initial request for seven more formations, was formed in 1942. The 79th Armoured Division was short-lived as a traditional armoured division, and in April 1943 was assigned to the development and use of Hobart's Funnies (specialised tanks). In this capacity, it did not act en masse, it maintained command and administrative control of its sub-units, they were assigned to other formations to provide specialised support as and when.Buckley (2004), p. 13
In addition, the 5th Armoured Division was notionally created in the United Kingdom in 1944-45 as a military deception scheme, part of Operation Fortitude#Fortitude South II.
Structure
Between May 1939 and May 1945, there were nine changes in the organisation of the divisions. When first formed, the Mobile Division had six light tank regiments in two cavalry brigades and a tank brigade of three medium regiments. The division was supported by a Pivot Group of two motorised infantry battalions and two artillery regiments. Mobile Division (Egypt) consisted of a light armoured brigade, a cavalry brigade, a heavy armoured group of two Royal Tank Regiments and a Pivot Group. On 25 May 1939, the Army decided that the organisation should change to an armoured division of a light and a heavy armoured brigade, each of three armoured regiments, totalling 349 tanks; 159 light cruisers, 108 light tanks, 58 heavy cruisers and 24 close support tanks. The two armoured brigades would have a Support Group that contained the divisional field artillery regiment, a mixed light anti-aircraft–anti-tank regiment, two motorised infantry battalions and the division's engineers. The support group provided whatever support the armoured brigades needed, being able to provide motorised infantry, field artillery, anti-tank artillery or light anti-aircraft artillery as needed.
The next change (on paper) was made in April 1940; the tank strength of the division was reduced to 340 tanks by changes in the armoured regiments, the two armoured brigades now became homogeneous, dropping their prefixes and the division's engineers were removed from the Support Group, becoming divisional troops under their own headquarters. Following the Battle of France, the Army realised that mixing light and cruiser tanks in the same brigade had been a mistake and that there were insufficient infantry and support units within the division.French (2000), p. 192 In October, the Support Group's motorised infantry battalions were transferred to the armoured brigades, each receiving one, while the Support Group was given a lorried infantry battalion, increasing the infantry strength of the division to three battalions. The mixed anti-aircraft–anti tank regiment was replaced by two specialised regiments. More engineers were added to the division. In Britain, an armoured car regiment was placed under the command of the division but not in the Middle East. While these theoretical changes were made, they did not reflect the armoured divisions' composition; in July, the 7th Armoured Division only had 65 cruiser tanks, lacking spare parts (some even lacking proper armament) while the division was operating two armoured regiments in each of its brigades.Playfair (1954), pp. 186, 188 In January 1941, the 1st Armoured Division, the best equipped armoured division in Britain, was 30 per cent below its tank establishment and was equipped with many obsolescent light tanks.French(2000), p. 107
In 1942, the British Army decided that an infantry brigade was needed in each division and on 27 February 1942 the next change was made for divisions operating in the Middle East; an armoured brigade would be replaced by an infantry brigade.French (2000), p. 269 The Support Group would be disbanded and a armoured car regiment would be added to the division. For tactical reasons, the battle formation in the Middle East became the Brigade Group, the division would now operate two brigade groups. The armoured brigade group would have three armoured regiments, a motor battalion, an artillery regiment (including an anti-tank battery of 16 guns; either 2-pounders or 6-pounders) as well as its three batteries of 25-pounder gun-howitzers, a light anti-aircraft battery of 18 guns, a field squadron of Royal Engineers and various other administration units. The infantry brigade group would consist of three motorised infantry battalions, an artillery regiment also with an integrated anti-tank battery, a light anti-aircraft battery, Royal Engineers and administration units. The divisional headquarters was given more staff and signal units and a headquarters was formed to control the artillery. Due to some armoured regiments being re-equipped with American tanks, the establishment of the division could vary between 130 and 150 tanks. In the United Kingdom, the brigade group was not adopted but the support group was abolished and an infantry brigade was added to the division to replace the second armoured brigade. The two artillery regiments, the anti-tank regiment and light anti-tank regiment were placed under the command of an artillery headquarters unit and additional administration units were attached to the division. Further changes were made to the armoured regiments and anti-aircraft tanks were incorporated into the division bringing the established strength to 227 tanks; 26 anti-aircraft tanks, 18 close support tanks and 183 cruiser tanks.
Prior to the Battle of Alam el Halfa, in August–September 1942, the armoured divisions in North Africa were again authorised to change; the armoured division became the basic battle formation again and the brigade groups were reorganised as they had previously. The artillery, anti-tank and anti-aircraft regiments would be put under the control of the Royal Artillery divisional headquarters and would be reinforced with additional batteries, the Royal Engineers would be reinforced and returned to the divisional engineer headquarters. The divisional tank establishment was increased to 186 and anti-aircraft tanks were also allocated to the division.
In April 1943, the armoured car regiment was removed from the division and replaced with an armoured reconnaissance regiment. Additional troops were allocated to the infantry brigade. The artillery regiments were also reorganised, one would now be equipped with self-propelled guns while the other would keep towed guns. The tank establishment was increased to 278 tanks; 214 cruisers, 34 anti-aircraft tanks and 30 close support tanks. In Britain, the 7th Armoured Division was re-equipped with Cromwell tanks, the only division to use them as their main battle tank, the others used M4 Sherman tanks. The Cromwell was used also by the armoured reconnaissance regiments of the 7th, 11th and Guards Armoured Divisions.Fortin, p. 82