История Британской Армии: от основания до современности.

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The history of the British Army spans over three and a half centuries since its founding in 1660 and involves numerous European wars, colonial wars and world wars. From the late 17th century until the mid 20th century, the United Kingdom was the greatest economic and imperial power in the world, and although this dominance was principally achieved through the strength of the Royal Navy (RN), the British Army played a significant role. as of 2015, there were 92,000 professionals in the regular army (including 2,700 Gurkhas) and 20,480 Volunteer Reserves. Britain has generally maintained only a small regular army during peacetime, expanding this as required in time of war, due to Britain's traditional role as a sea power. Since the suppression of Jacobitism in 1745, the British Army has played little role in British domestic politics (except for the Curragh incident), and, apart from Ireland, has seldom been deployed against internal threats to authority (one notorious exception being the Peterloo Massacre). The British Army has been involved in many international conflicts, including the Napoleonic Wars, the Crimean War and both World War I and World War II. Historically, it contributed to the expansion and retention of the British Empire. The British Army has long been at the forefront of new military developments. It was the first in the world to develop and deploy the tank, and what is now the Royal Air Force (RAF) had its origins within the British Army as the Royal Flying Corps (RFC). At the same time the British Army emphasises the continuity and longevity of several of its institutions and military tradition.

The order of seniority for the most senior line regiments in the British Army is based on the order of seniority in the English army. Scottish and Irish regiments were only allowed to take a rank in the English army from the date of their arrival in England or the date when they were first placed on the English establishment. For example, in 1694 a board of general officers was convened to decide upon rank of English, Irish and Scots regiments serving in the Netherlands, the regiment that became known as the Scots Greys were designated as the 4th dragoons because there were three English regiments raised prior to 1688 when the Scot Greys were first placed on the English establishment. In 1713 when a new board of general officers was convened to decide upon rank of several regiments, the seniority of the Scots Greys was reassessed and based on their entry into England in June 1685. At that time there was only one English regiment of dragoons and so after some delay the Scots Greys obtained the rank of 2nd dragoons in the British Army.

By the middle of the century, the army's administration had developed the form which it would retain for more than a hundred years. A number of independent offices and individual officers were responsible for various aspects of Army administration. The most important were the Commander in Chief of the Forces, the Secretary at War, and the twin Secretaries of State; most of whose military responsibilities were passed to a new Secretary of State for War in 1794. Others who performed specialist functions were the controller of army accounts, the Army Medical Board, the Commissariat Department of HM Treasury, the Board of General Officers, the Judge Advocate General of the Forces, the Commissary General of Muster, the Paymaster of the Forces. The Militia did not belong to the Army and was administrated by the Home Office through the Lord Lieutenants. In the field, a commander's staff consisted of an Adjutant General (who handled finance, troop returns and legal matters), and a Quartermaster General (who was responsible for billeting and organising movements). There were separate commanders of the Artillery, and Commissary Officers who handled the supplies. The commander of an Army might also have a Military Secretary, responsible for appointments, court martials and official correspondence. Infantry and cavalry units had originally been known by the names of their colonels, such as "Sir John Mordaunt's Regiment of Foot". This could be confusing if colonels succeeded each other rapidly; and two regiments (the Buffs and the Green Howards) had to be distinguished by their facing colour in official correspondence because for several years, both had colonels named Howard. In time, these became the official names of the regiments. In 1751 a numeral system was adopted, with each regiment gaining a number according to their rank in the order of precedence, so John Mordaunt's Regiment became the 47th Regiment of Foot. The later Jacobite risings were centred in the Scottish Highlands. From the late 17th century, the Government had organised Independent Highland Companies in the area, from clans which supported the Hanoverian monarchs or the Whig governments, to maintain order or influence in the Highlands. In 1739 the first full regiment, the 42nd Regiment of Foot, was formed in the region. Towards the end of the 18th century, the battalion became the major tactical unit of the army. On the continent of Europe, where large field formations were usual, a regiment was a formation of two or more battalions, under a colonel who was a field commander. The British Army, increasingly compelled to disperse units in far flung colonial outposts, made the battalion the basic unit, under a lieutenant colonel. The function of the regiment became administrative rather than tactical. The colonel of a regiment remained an influential figure but rarely commanded any of its battalions in the field. Many regiments consisted of one battalion only, plus a depot and recruiting parties in Britain or Ireland if the unit was serving overseas. Where more troops were required for a war or garrison duties, second, third and even subsequent battalions of a regiment were raised, but it was rare for more than one battalion of a regiment to serve in the same brigade or division.

The Seven Years' War, which took place from 1755 to 1763, has sometimes been described as the first true world war, in that conflict took place in almost every continent and on almost all the oceans. Although there were early setbacks, British troops eventually were victorious in every theatre. The war can be said to have started in North America, where it was known as the French and Indian War. The early years saw several British defeats. The British units first despatched to the Continent were untrained in the bush warfare they met. To provide light infantry, several corps such as Rogers' Rangers were raised from the colonists. (A light infantry regiment, the 80th Regiment of Light Armed Foot, was raised by Colonel Thomas Gage, but subsequently disbanded). During the war, General James Wolfe amalgamated companies from several regiments into an ad hoc unit, the Louisbourg Grenadiers. There were also disagreements between high ranking British officers and the provincial troops recruited from the colonies. It was laid down that even the most senior Provincial officers were subordinate to comparatively junior officers in the British Army. The first concern of the colonists' representatives was the protection of the settlers from raids by Native American war parties, while the British generals often had different strategic priorities. Partly through the naval superiority gained by the Royal Navy, Britain was eventually able to deploy superior strength in North America, winning the decisive Battle of the Plains of Abraham at Quebec City and conquering New France. Similarly, in the Indian subcontinent, the French East India Company and the militaries of the most powerful rulers of the Mughal Empire were defeated after the prolonged Third Carnatic War, allowing the steady expansion of British East India Company controlled territory. In Europe, although Britain's allies (chiefly the Royal Prussian Army) carried the main burden of the struggle, British troops eventually played an important role at the decisive Battle of Minden. With the defeat of France, the British government no longer sought actively to curry the favour of Native Americans. Urged by his superiors to cut costs, Commander in Chief General Jeffery Amherst initiated policy changes that helped prompt Pontiac's War in 1763, an uprising against the British military occupation of the former New France. Amherst was recalled during the war and replaced as commander in chief by Thomas Gage.

The American Revolution had its origins in George III's unpopular attempts to station a permanent garrison force in British America, and in the taxes, duties, and customs levied on colonies to fund the force such as the Sugar Act, the Stamp Act, and the Townshend Acts. North Americans in the Thirteen Colonies objected to both the idea of a "standing army" and "taxation without representation" and increasingly denied that the Parliament of Great Britain should have authority or, eventually, sovereignty over the colonies, positions which Parliament viewed as challenges to parliamentary supremacy. For the British Army, the American War of Independence had its origins in the military occupation of Boston in 1768. Tensions between the army and local civilians helped contribute to the Boston Massacre of 1770, but outright warfare did not begin until 1775, when the "Minutemen" militias in the Massachusetts Bay Province attacked an army detachment sent to seize colonial munitions at Battles of Lexington and Concord. When the war ended in 1783 with the British government forced to recognize its defeat and U. S. independence under the Treaty of Paris, many United Empire Loyalists fled north to British Canada, where many subsequently served with the British Army or colonial militias. The Army itself had established many British units during the war to serve in North America or provide replacements for garrisons. All but three (the 23rd Regiment of (Light) Dragoons and two Highland infantry regiments, the 71st and 78th Foot) were disbanded immediately after the war. The Army was forced to adapt its tactics to the poor communications and forested terrain of North America. Large numbers of light infantry (detached from line units) were organised, and the formerly rigid drills of the line infantry were modified to a style known as "loose files and an American scramble". While the British defeated the colonists in most of the set piece battles of the war, none of these had any decisive result, whereas the British defeats at the Battle of Saratoga and Siege of Yorktown adversely affected British morale, prestige and manpower. Historians have examined the issue of responsibility for the defeat in terms of personalities. They also have explored such issues as communications and supply, a lack of defined objectives, and the underestimation of the American forces.

The British Army during the French Revolutionary and Napoleonic Wars experienced a time of rapid change. At the beginning of the French Revolutionary Wars in 1793, the army was a small, awkwardly administered force of barely 40,000 men. By the end of the Napoleonic Wars, the army had been through a series of structural, recruitment, tactical and training reforms and its manpower had vastly increased. At its peak, in 1813, the regular army contained over 250,000 men. The British infantry was "the only military force not to suffer a major reverse at the hands of Napoleonic France."

During the long reign of Queen Victoria, British society underwent great changes such as the Industrial Revolution and the enactment of liberal reforms within Britain. The Victorian era was also marked by the steady expansion and consolidation of the British Empire. The role of the military was to defend the Empire and, for the Army, to control the natives. The Industrial Revolution had changed the Army's weapons, transport and equipment, and social changes such as better education had prompted changes to the terms of service and outlook of many soldiers. Nevertheless, it retained many features inherited from the Duke of Wellington's army, and since its prime function was to maintain the expanding British Empire, it differed in many ways from the conscripted armies of continental Europe. For example, it did not undertake large scale manoeuvres. Indeed, the Chobham Manoeuvres of 1853 involving 7,000 troops were the first such manoeuvres since the Napoleonic Wars. The Crimean War (1854–56) had so many blunders and failures—most famously the ill advised "Charge of the Light Brigade"—that it became an iconic symbol of logistical, medical and tactical failures and mismanagement. Public opinion in Britain was outraged at the failures of traditional methods in the face of modernization everywhere else in British society; the newspapers demanded drastic reforms, and parliamentary investigations exposed a multiplicity of grave problems. However, the reform campaign was not well organized. This allowed the traditional aristocratic leadership of the Army to pull itself together and block all serious reforms. No one was punished. The outbreak of the Indian Rebellion of 1857 shifted attention to the heroic defense of British interests by the Army, and further talk of reform went nowhere. The demand for professionalization was, however, achieved by Florence Nightingale, who gained worldwide attention for pioneering and publicizing modern nursing while treating the wounded.

The Crimean War demonstrated that reforms were urgently needed to guarantee that the Army could protect both the home nation and the Empire. Nevertheless, reform was impossible until the 1870s when the army assumed the form it took in 1914. Prime Minister William Ewart Gladstone paid little attention to military affairs apart from budgets, but as he and the rest of stunned Europe watched the German coalition led by Prussia crushed France in a matter of weeks, the myriad old inadequacies of the British army set the agenda. His Secretary of State for War, Edward Cardwell proposed far reaching reforms that Gladstone pushed through the Parliament of the United Kingdom. The Prussian system of professional soldiers with up to date weapons was far superior to the traditional system of gentlemen soldiers that Britain used. The Cardwell Reforms centralised power in the War Office, abolished the purchase of officers' commissions, and created reserve forces stationed in Britain by establishing short terms of service for enlisted men. Edward Cardwell (1813–1886) as Secretary of State for War (1868–1874) designed the reforms that Gladstone promoted in the name of efficiency and democracy. In 1868 he abolished flogging, raising the private soldier status to more like an honourable career. In 1870 Cardwell abolished "bounty money" for recruits, discharged known bad characters from the ranks. He pulled 20,000 soldiers out of self governing colonies, like Canada after Canadian Confederation, which learned they had to help defend themselves. The most radical change, and one that required Gladstone's political muscle, was to abolish the system of officers obtaining commissions and promotions by purchase, rather than by merit. The system meant that the rich landholding families controlled all the middle and senior ranks in the army. Promotion depended on the family's wealth, not the officer's talents, and the middle class was shut out almost completely. British officers were expected to be gentlemen and sportsmen; there was no problem if they were entirely wanting in military knowledge or leadership skills. From the Tory perspective it was essential to keep the officer corps the domain of gentlemen, and not a trade
for professional experts. They warned the latter might menace the oligarchy and threaten a military coup; they preferred an inefficient army to an authoritarian state. The unification of Germany by Otto von Bismarck made this reactionary policy too dangerous for a great empire to risk. The bill, which would have compensated current owners for their cash investments, passed the Commons in 1871 but was blocked by the House of Lords. Gladstone then moved to drop the system without any reimbursements, forcing the Lords to backtrack and approve the original bill. Liberals rallied to Gladstone's anti elitism, pointing to the case of Lord Cardigan (1797–1868), who spent £40,000 for his commission and proved utterly incompetent in the Crimean war, where he ordered the disastrous "Charge of the Light Brigade" in 1854. Cardwell was not powerful enough to install a general staff system; that had to await the 20th century. He did rearrange the war department. He made the office of Secretary of State for War superior to the Army's commander in Chief; the commander was His Royal Highness the Duke of Cambridge (1819–1904), the Queen's first cousin, and an opponent of the reforms. The surveyor general of the ordnance, and the financial secretary became key department heads reporting to the Secretary. The militia was reformed as well and integrated into the Army. The term of enlistment was reduced to 6 years, so there was more turnover and a larger pool of trained reservists. The territorial system of recruiting for regiments was standardised and adjusted to the current population. Cardwell reduced the Army budget yet increased its strength of the army by 25 battalions, 156 field guns, and abundant stores, while the reserves available for foreign service had been raised tenfold from 3,500 to 36,000 men.

The British Army during World War I could trace its origins to the increasing demands of imperial expansion together with inefficiencies highlighted during the Crimean War, which led to the Cardwell and Childers Reforms of the late 19th century. These gave the British Army its modern shape, and defined its regimental system. The Esher Report in 1904, recommended radical reform of the British Army, such as the creation of an Army Council, a General Staff and the abolition of the office of Commander in Chief of the Forces and the creation of a Chief of the General Staff. The Haldane Reforms in 1907, created an expeditionary force of seven divisions, it also reorganized the volunteers into a new Territorial Force of fourteen cavalry brigades and fourteen infantry divisions, and changed the old militia into the special reserve to reinforce the expeditionary force. The British Army was different from the French and German Armies at the beginning of the conflict in that it was made up from volunteers not conscripts. It was also considerably smaller than its French and German counterparts. The British entry into World War I in August 1914 saw the bulk of the changes in the Haldane reforms put to the test. The British Expeditionary Force (BEF) of six divisions was quickly sent to the Continent, while the Territorial Forces fourteen divisions and Reserves were mobilised as planned to provide a second line. During the war there were three distinct British Armies. The 'first' army was the small volunteer force of about 400,000 soldiers (comprising the Regular Army of 247,000 and Territorial Force of 145,000), over half of which were posted overseas to garrison the British Empire. This total included the Regular Army and reservists in the Territorial Force. Together they formed the BEF, for service in France and became known as the Old Contemptibles. The 'second' army was Kitchener's Army, formed from the volunteers in 1914–1915, which was destined to go into action at the Battle of the Somme. The 'third' was formed after the introduction of conscription in January 1916 and by the end of 1918 the British Army had reached its peak of strength of four million men and could field over seventy divisions. The vast majority of the British Army fought in France and Belgium on the Western Front but some units were engaged in the Mediterranean, the Middle East, Africa and Mesopotamia, mainly against the Ottoman Empire. One battalion also fought in China during the Siege of Tsingtao.

In 1919–1920 there was a short lived boom in the British economy, caused by a rush of investment pent up during the war years and another rush of orders for new shipping to replace the millions of tons lost. But, following the boom, interwar Britain faced serious economic woes beginning with the Depression of 1920–1921. Heavy defence cuts were consequently imposed by the British Government in the early 1920s as part of a reduction in public expenditure known as the "Geddes Axe" after Sir Eric Geddes. The Government introduced the Ten Year Rule, stating its belief that Britain would not be involved in another major war for 10 years from the date of review. This ten year rule was continually extended until it was abandoned in 1932. One new corps was the Royal Signals, formed in 1920 from within the Royal Engineers to take over the role of providing communications. Within the cavalry, sixteen regiments were amalgamated into eight, producing the "Fraction Cavalry"; units with unwieldy titles combining two regimental numbers. There was a substantial reduction in the number of infantry battalions and the size of the Territorial Force, which was renamed the Territorial Army. On 31 July 1922, the Army also lost six Irish regiments (5 infantry and 1 cavalry) on the creation of the Irish Free State. Until the early 1930s, the Army was effectively reduced to the role of imperial policeman, concentrated on responding to the small imperial conflicts that rose up across the Empire. It was unfortunate that certain of the officers who rose to high rank and positions of influence within the army during the 1930s were comparatively backward looking. This meant that trials such as the Experimental Mechanized Force of 1927–28 did not go as far as they might have.

One of the first post war campaigns that the Army took part in was the Allied intervention in the Russian Civil War in 1919 to assist the "White Army" against the Communist Bolsheviks during their Civil War. Another was the Third Anglo Afghan War (1918–19), fought in Afghanistan after the Emirate of Afghanistan invaded British India. The British Army was also maintaining occupation forces in the defeated Central Powers of World War I. In Weimar Germany, a British Army of the Rhine (BAOR) was established for the Allied occupation of the Rhineland. The BAOR would remain in existence until 1929 when British forces were withdrawn. Another British occupation force was based in Allied occupied Constantinople in Turkey, and a number of British units fought against the Turkish National Movement during the Turkish War of Independence. A small British Military Mission was also advising the Polish Army during the Polish–Soviet War (1919–1921). The Army, throughout the inter war period, also had to deal with quelling paramilitary organisations seeking the removal of the British. In Iraq, British forces put down the Iraqi revolt of 1920 against British rule in Mandatory Iraq. In British Somaliland, Diiriye Guure's men resumed their campaign against the British, a campaign that had first begun in 1900. The operations against him were prominent due to the newly formed RAF being instrumental in his defeat. The Army also took part in operations in Ireland against the IRA during the Anglo Irish War. Both sides committed atrocities, some units becoming infamous, such as the paramilitary Black and Tans where many recruits were veterans of the First World War. The British Army was also supporting Indian Army operations in the North West Frontier of British India against numerous tribes, known collectively as the Pathans, hostile to the British. The Army had been operating in the volatile North West Frontier area since the mid 19th century. The last major uprising that the Army had to deal with before the start of the Second World War, was the uprising in Palestine that began in 1936.

By the mid 1930s, Nazi Germany was becoming increasingly aggressive and expansionist. Another war with Germany appeared certain. The Army was not properly prepared for such a war, lagging behind the technologically advanced and potentially much larger Heer of the German Wehrmacht. With each armed service vying for a share of the defence budget, the Army came last behind the Royal Navy and Royal Air Force in allocation of funds. During the years after the First World War, the Army's strategic concepts had stagnated. Whereas Germany, when it began rearming following Hitler's rise to power, eagerly embraced concepts of mechanised warfare as advocated by individuals such as Heinz Guderian, many high ranking officers in Britain had little enthusiasm for armoured warfare, and the ideas of Basil Liddell Hart and J. F. C. Fuller were largely ignored. One step to which the Army was committed was the mechanisation of the cavalry, which had begun in 1929. This first proceeded at a slow pace, having little priority. By the mid 1930s, mechanisation in the British Army was gaining momentum and on 4 April 1939, with the mechanisation process nearing completion, the Royal Armoured Corps was formed to administer the cavalry regiments and Royal Tank Regiment (except for the Household Cavalry). The mechanisation process was finally completed in 1941 when the Royal Scots Greys abandoned their horses. After the Munich Crisis in 1938, a serious effort was undertaken to expand the Army, including the doubling in size of the Territorial Army, helped by the reintroduction of conscription in April 1939. By mid 1939 the Army consisted of 230,000 Regulars and 453,000 Territorials and Reservists. Most Territorial formations were understrength and badly equipped. Even this army was dwarfed, yet again, by its continental counterparts. Just before the war broke out, a new British Expeditionary Force was formed. By the end of the year, over 1 million had been conscripted into the Army. Conscription was administered on a better planned basis than in the First World War. People in certain reserved occupations, such as dockers and miners, were exempt from being called up as their skills and labour were necessary for the war effort. Between 1938 and 1939, following a substantial expansion in the Army, a number of new organisations were formed, including the Auxiliary Territorial Service for women in September 1938; its duties were vast, and helped release men for front line service.

The British Army in 1939 was a volunteer army that introduced conscription shortly before the declaration of war with Germany. During the early years of the Second World War, the army suffered defeat in almost every theatre it deployed, due to a variety of reasons, mainly because of decisions made before the war and politicians and senior commanders being unclear on what the army's role was. With mass conscription the expansion of the army was reflected in the creation of more divisions, army corps, armies and army groups. From 1943, the British Army's fortunes turned and it hardly suffered a strategic defeat. The pre war British Army was trained and equipped to garrison and police the British Empire and, as became evident during the war, was woefully unprepared and ill equipped to conduct a war against multiple enemies on multiple fronts. At the start of the war the army was small in comparison to its enemies', and remained an all volunteer force until 1939. By the end of the war the British Army had grown to number over 3.5 million. The British Army fought around the world, with campaigns in Norway, Belgium and France in 1940 and, after the collapse of both the latter countries, in Africa, the Mediterranean and Middle East and the Far East. After a series of setbacks, retreats and evacuations the British Army and its Allies eventually gained the upper hand. This started with victory over the Italian and German forces in the Tunisia Campaign. Italy was then forced to surrender after the invasion of Sicily and mainland Italy. Then in the last years of the war, the British Army, with its allies, returned to France, driving the German Army back into Germany and in the Far East forced the Japanese back from the Indian border into Burma. Both the Germans and Japanese were defeated by 1945, and surrendered within months of each other. With the expansion of the British Army to fight a world war, new armies had to be formed, and eventually army groups were created to control even larger formations. In command of these new armies, eight men would be promoted to the rank of field marshal. The army commanders not only had to manage the new armies, but also a new type of soldier in formations that had been created for special service, which included the Special Air Service, Army Commandos and the Parachute Regiment.

The creation of the North Atlantic Treaty Organization (NATO) in 1949 reflected the beginning of the "Cold War" between the ideologically divided "Western Allies" and the Eastern Communist powers, controlled by the Soviet Union; they created their own NATO equivalent in 1955, known as the Warsaw Pact. An integral part of NATO's defences in the now divided Europe was the British Army of the Rhine (BAOR) in West Germany, the British Army's new overseas 'home' that replaced independent India. The British Army, just as in the aftermath of World War I, had established BAOR in the immediate aftermath of the war which was centred on I Corps (upon its re establishment in 1951), at its peak reaching about 80,000 troops. At home, there were five regional commands: Eastern, Western, Northern, Scottish, and Southern Command, which all eventually merged to become HQ United Kingdom Land Forces or UKLF in 1972. The Army was beginning to draw down its forces, beginning the demobilisation of the British Armed Forces shortly after the end of the war. The Territorial units were placed in 'suspended animation', being reconstituted upon the reformation of the TA in 1947. On 1 January 1948, National Service, the new name for conscription, formally came into effect. The Army was, however, being reduced in size upon the end of British rule in India and decolonization, including the second battalions of every Line Infantry regiment either amalgamating with the 1st Battalions to maintain the 2nd Battalion's history and traditions, or simply disband, thus ending the two battalion policy implemented by Childers in 1881. This proved too severe a decision for the overstretched Army, and a number of regiments reformed their second battalion in the 1950s. The year 1948 also saw the Army receive four Gurkha regiments (eight battalions in total) transferred to them from the Indian Army and were formed into the Brigade of Gurkhas, initially based in Malaya. More reforms of the armed forces took place with the 1957 Defence White Paper, which saw further reductions implemented; the Government realised after the debacle of the Suez Crisis that Britain was no longer a global superpower and decided to withdraw from most of its commitments in the world, limiting the armed forces to concentrating on NATO, with an increased reliance upon nuclear weapons. The White Paper announced that the Army would be reduced in size from about 330,000 to 165,000, with National Service ending by 1963 (it officially ended on 31 December 1960, with the last conscript being discharged in May 1963) with the intention of making the Army into an entirely professional force. This enormous reduction in manpower led to, between 1958 and 1962, eight cavalry and thirty infantry regiments being amalgamated, the latter amalgamations producing fifteen single battalion regiments. Brigade cap badges superseded the regimental cap badge in 1959. Many of the regiments created during the 1957 White Paper would have only a brief existence, most being amalgamated into new 'large' regiments The Queen's, Royal Fusiliers, Royal Anglian, Light Infantry, Royal Irish Rangers, and the Royal Green Jackets—all of whose 'junior' battalions were disbanded by the mid 1970s. Two regiments The Cameronians (Scottish Rifles) and The York and Lancaster Regiment—opted to be disbanded rather than amalgamated. The fourteen administrative brigades (created in 1948) were replaced by six administrative divisions in 1968, with regimental cap badges being re introduced the following year. The Conservative Government came to power in 1970, one of its pledges included the saving of the Argyll and Sutherland Highlanders after a popular campaign to save it had been provoked by the announcement of its intended demise. The Government also decided to stop the planned amalgamation of The Gloucestershire Regiment with The Royal Hampshire Regiment. Further cavalry and infantry regiments were, however, amalgamated between 1969 and 1971, with six cavalry (into three) and six infantry (also into three) regiments doing so. For the structure of the Army during this period, see List of British Army regiments (1962). HQ UK Land Forces was formed in 1972, and the previous home commands were effectively downgraded to districts.

In the immediate aftermath of the Asian theater of World War II, the Army was tasked with reoccupying former British territories captured by the Imperial Japanese Armed Forces such as Malaya, Singapore, and Hong Kong. The British Army also played an active part, if only briefly, in the military actions by other European nations in their attempts to restore their pre–World War II governance, occupation, and control of South Eastern Asian countries. For example, British and Indian Army forces were sent to the island of Java in the Dutch East Indies in September 1945 to disarm and help repatriate the Japanese occupation forces. It was a month after the local nationalists—who had been provided with arms by the Japanese—had declared an independent Indonesia. The situation in Java was quite chaotic with much violence taking place. The British and Indian forces experienced fierce resistance from the nationalists; the former Japanese occupation force was also employed by the British to help maintain order, and fought alongside the British and Indian forces. Dutch forces gradually arrived in number and the British and Indians left by November 1946. A similar situation existed in French Indochina after Viet Minh leader Ho Chi Minh declared the independence of Vietnam on 2 September 1945, beginning the War in Vietnam. British and Indian troops, commanded by Major General Douglas Gracey, were deployed to occupy the south of the country shortly afterwards, while the Republic of China attempted to occupy the northern areas of Vietnam. Vietnam was at this time in chaos and the population did not want French rule restored. The British military decided to rearm numerous French POWs—who then went on a rampage—and British forces also re armed Japanese troops to help maintain order. The British and Indians departed by February 1946 and the First Indochina War began shortly afterwards. The Indochina Wars would continue for more than twenty years.

The latter part of the 1940s saw the British start to begin to withdraw from the Empire, the Army playing a prominent role in its dismantlement. The first colony the British withdrew from was India, the largest British possession as measured by population, though not the largest by geographical area. In 1947 the British government announced India would become independent on 15 August, after being separated into two countries, one mostly Muslim (Pakistan) and the other mostly Hindu (India). The British Army subsequently did not play a major role in the First Indo Pakistani War between these two countries. The last British Army unit to leave active service in the Indian subcontinent was the 1st Battalion, The Somerset Light Infantry (Prince Albert's) on 28 February 1948. In the 1948 Palestine war, there was a surge in attacks against the British mandate and occupation by Zionist organisations such as Irgun and the Stern Gang after the British attempted to limit Jewish immigration into Palestine. British military and other forces eventually withdrew in 1948 and the State of Israel was established on 14 May. Elsewhere, within British territories, Communist guerrillas launched an uprising in Malaya, starting the Malayan Emergency. In the early 1950s, trouble began in Cyprus, and in Kenya—the Mau Mau uprising. In the Cyprus Emergency, a Greek nationalist organisation known as EOKA sought unity with Greece, the situation being stabilised just before Cyprus was given independence in 1960.

Elsewhere, the Army withdrew from the Suez Canal Zone in Egypt in 1955. The following year, along with France and Israel, the British invaded Egypt in a conflict known as the Suez War, after the Egyptian leader, President Nasser nationalised the Suez Canal which privately owned businesses in Britain and France owned shares in. The British Army contributed forces to the amphibious assault on Suez and British paratroopers took part in the airborne assault. This brief war was a military success. However, international pressure, especially from the US government, soon forced the British government to withdraw all their military forces soon afterwards. British military forces were replaced by United Nations Emergency Force peacekeeping troops. In the 1960s two conflicts featured heavily with the Army, the Aden Emergency Among those killed in the attacks by the RUC was Trooper Hugh McCabe, the first British soldier to die in The Troubles. The troops were initially welcomed by the Catholic community as they believed the troops would protect them; however, this developed into opposition as the troops began to support the RUC, and the Provisional Irish Republican Army (PIRA), a militant break away from the original Irish Republican Army which had been quiet since the 1962 cessation of the Border Campaign, began to target British troops. The British Army's operations in the early phase of its deployment had it placed in a policing role, for which, in many cases, it was ill suited. This involved seeking to prevent confrontations between the Catholics and Protestants, as well as putting down riots and stopping Republican and Loyalist paramilitary groups from committing terrorist attacks. However, as the Provisional Irish Republican Army campaign grew in ferocity in the early 1970s, the Army was increasingly caught in a situation where its actions were directed against the IRA and the Catholic Irish nationalist community which harboured it. In the early period of the conflict, British troops mounted several major field operations. The first of these was the Falls Curfew of 1971, when over 3,000 troops imposed a 3 day curfew on the Falls Road area of Belfast and fought a sustained gun battle with local IRA men. In Operation Demetrius in June 1971, 300 paramilitary suspects were interned without trial, an action which provoked a major upsurge in violence. The largest single British operation of the period was Operation Motorman in 1972, when about 21,000 troops were used to restore state control over areas of Belfast and Derry, which were then controlled by republican paramilitaries. The British Army's reputation suffered further from an incident in Derry on 30 January 1972, Bloody Sunday in which 13 Catholic civilians were murdered by The Parachute Regiment. The biggest single loss of life for British troops in the conflict came at Narrow Water, where eighteen British soldiers were killed in a PIRA bomb attack on 27 August 1979, on the same day Lord Mountbatten of Burma was assassinated by the PIRA in a separate attack. In all almost 500 British troops died in Northern Ireland between 1969 and 1997. By the late 1970s, the British Army was replaced to some degree as "frontline" security service, in preference for the local Royal Ulster Constabulary and the Ulster Defence Regiment (raised 1970) as part of the Ulsterisation policy. By the 1980s and early 1990s, British Army casualties in the conflict had dropped. Moreover, British Special Forces had some successes against the PIRA – see Operation Flavius and the Loughgall Ambush. Nevertheless, the conflict tied up over 12,000 British troops on a continuous basis until the late 1990s and was ended with the Good Friday Agreement which detailed a path to a political solution to the conflict. Operation Banner came to an end in 2007 making it the longest continuous operation in the British Army's history, lasting over thirty eight years. Troop numbers were reduced to 5,000.

In 1980, the Special Air Service emerged from its secretive world when its most high profile operation, the ending of the Iranian Embassy Siege in London, was broadcast live on television. By the 1980s, even though the Army was being increasingly deployed abroad, most of its permanent overseas garrisons were gone, with the largest remaining being the BAOR in Germany, while others included Belize, Brunei, Gibraltar, and Hong Kong.

One remaining garrison provided by the Royal Marines was the Falkland Islands in the South Atlantic, 6,000 to 8000 mile (12875 km) (11,000 to 15,000 km) from Britain. The Argentinians invaded the Falklands in April 1982. The British quickly responded and the Army had an active involvement in the campaign to liberate the Falklands upon the landings at San Carlos, taking part in a series of battles that led to them reaching the outskirts of the capital, Stanley. The Falklands War ended with the formal surrender of the Armed Forces of the Argentine Republic on 14 June.

The collapse of the Soviet Union, ending the Cold War, saw a new defence white paper, Options for Change produced. This saw inevitable reductions in the British armed forces. The Army experienced a substantial cut in its manpower (reduced to about 120,000), Nine of the Army's administrative corps were amalgamated to form the Royal Logistic Corps and the Adjutant General's Corps. One major development was the disbandment of the Women's Royal Army Corps (though the largest elements were absorbed by the AGC) and their integration into services that had previously been restricted to men; however, women were still prohibited from joining armoured and infantry units. The four Gurkha regiments were amalgamated to form the three battalion Royal Gurkha Rifles, reduced to two in 1996 just before the handover of Hong Kong to the People's Republic of China in 1997. The Labour Party became the country's new government and after their victory in the 1997 general election a new defence white paper was prepared, known as the Strategic Defence Review (1998). Some of the Army's reforms included the creation of two deployable divisions 1st (UK) Armoured Division and 3rd Mechanised Division, with the 1st Division being based in Germany—and three 'regenerative' divisions 2nd, 4th, and 5th Divisions. The 16 Air Assault Brigade was formed from 24 Airmobile Brigade and elements of 5 Airborne Brigade to provide the Army with increased mobility, and would include the Westland WAH 64 Apache attack helicopter. Other attempts to make the Army more mobile was the creation of the Joint Rapid Reaction Force, intended to provide a corps sized force capable of reacting quickly to situations similar to Bosnia. The Army Air Corps's helicopters also helped form the multi service Joint Helicopter Command. Another defence review was published in 2004, known as Delivering Security in a Changing World. The defence white paper stated that the Army's manpower would be reduced by 1,000, with four infantry battalions being cut and the manpower being redistributed elsewhere. One of the most radical aspects of the reforms was the announcement that most single battalion regiments would amalgamate into large regiments, with most of the battalions retaining their previous regimental titles in their battalion names. The TA would also be further integrated into the Army, with battalions being numbered into the regiment's structure. These are reminiscent, in some respects, to the Cardwell Childers reforms and the 1960s reforms. The elite units of the Army are also playing an increasingly prominent role in the Army's operations and the SAS was allocated further funds in the 2004 defence paper, conveying the SAS's increasing importance in the War on Terror. Another élite unit became operational in 2005, the Special Reconnaissance Regiment. The 1st Battalion of the Parachute Regiment became the core of a tri service Special Forces Support Group formed in 2006 to support the SAS and the Navy's SBS, being described as the Army's equivalent to the U. S. Army Rangers.

The end of the Cold War did not provide the British Army with any respite, and the political vacuum left by the Soviet Union has seen a surge of instability in the world. Saddam Hussein's Iraq invaded Kuwait, one of its neighbours, in 1990, provoking condemnation from the United Nations, primarily led by the United States. The Gulf War and the British contribution, known as Operation Granby, was large, with the Army providing about 28,000 troops and 13,000 vehicles, mostly centred on 1 (UK) Armoured Division. After air operations ended, the land campaign against Iraq began on 24 February. 1st Armoured Division took part in the left hook attack that helped destroy many Iraqi units. The ground campaign had lasted just 100 hours, Kuwait being officially liberated on 27 February. The British Army has also played an increasingly prominent role in peacekeeping operations, gaining much respect for its comparative expertise in the area. In 1992, during the wars in the Balkans provoked by the gradual disintegration of Yugoslavia, UN forces intervened in the Croatian War of Independence and later the Bosnian War. British forces contributed as part of UNPROFOR (United Nations Protection Force). The force was a peacekeeping one, but with no peace to keep, it proved ineffective and was replaced by NATO's Implementation Force, though this was in turn replaced the following year by the Stabilisation Force in Bosnia and Herzegovina. As of 2005, Britain's contribution numbers about 3,000 troops. In 1999 the UK took a lead role in the NATO war against Slobodan Milošević's Federal Republic of Yugoslavia in the Kosovo War. After the air war ended, the Parachute Regiment and Royal Gurkha Rifles provided the spearhead for ground forces entering Kosovo. In 2000, British forces, as part of Operation Palliser, intervened in the Sierra Leone Civil War, with the intention of evacuating British, Commonwealth and EU citizens. The SAS also played a prominent role when they, along with the Paras, launched the successful Operation Barras to rescue 6 soldiers of the Royal Irish Regiment being held by the rebels. The British force remained and provided the catalyst for the stabilisation of the country. The early 21st century saw the world descend into a new war after the 9/11 terrorist attacks on the World Trade Center in New York City by Al Qaida: the War on Terrorism. A US led invasion of Taliban ruled Afghanistan followed, with the British contribution under Operations Veritas led by the RN and RAF; the most important Army element being the SAS. The British Armed Forces continued contributing to NATO's International Security Assistance Force through Operation Herrick between 2002 and 2014 and then to its successor the Resolute Support Mission under Operation Toral until 2021. The British later took part in the invasion of Iraq in 2003, Britain's contribution being known as Operation Telic, The Army played a more significant role in the Iraq War than the War in Afghanistan, deploying a substantial force, centred on 1 (UK) Armoured Division with, again, around 28,000 troops. The war began in March and the British fought in the southern area of Iraq, eventually capturing the second largest city, Basra, in April. The Army remained in Iraq upon the end of the war and subsequently led the Multi National Division (South East), with the Army presence in Iraq numbering about 5,000 soldiers.