United Kingdom of Great Britain and Ireland
The United Kingdom of Great Britain and Ireland was established by the Acts of Union in 1801 that united the Kingdom of Great Britain and the Kingdom of Ireland into one sovereign state. It continued in this form until 1927, when it evolved into the United Kingdom of Great Britain and Northern Ireland, after the Irish Free State gained a degree of independence in 1922.
Rapid industrialisation that began in the decades prior to the state's formation continued up until the mid-19th century. The Great Irish Famine, exacerbated by government inaction in the mid-19th century, led to demographic collapse in much of Ireland and increased calls for Irish land reform. The 19th century was an era of Industrial Revolution, and growth of trade and finance, in which Britain largely dominated the world economy. Outward migration was heavy to the principal British overseas possessions and to the United States.
The UK, from its islands off the coast of Europe, financed the coalition that defeated France during the Napoleonic Wars, and developed its dominant Royal Navy enabling the British Empire to become the foremost world power for the next century. From the defeat of Napoleon to World War I, Britain was almost continuously at peace with the Great Powers. However, the UK did engage in extensive wars in Africa and Asia, such as the Opium Wars, to extend its empire and influence. The Colonial Office and India Office ruled through a small number of administrators who managed the units of the empire locally, while local institutions developed. British India was by far the most important overseas possession. In overseas policy, the central policy was free trade, which enabled British financiers and merchants to operate successfully in otherwise independent countries, as in South America. Beginning in earnest in the second half of the 19th century, the Imperial government granted increasing autonomy to local governments in colonies where white settlers were politically dominant, with this process resulting in Canada, Australia, New Zealand, Newfoundland and South Africa becoming self-governing dominions. While these remained part of the Empire, they were permitted greater management of their internal affairs, with Britain remaining responsible for their foreign and trade policies.
With respect to other powers, the British remained non-aligned until the 20th century when the growing naval power of the German Empire came to be seen as an existential threat to the British Empire. In response, London began to cooperate with Japan, France and Russia, and moved closer to the United States. Although not formally allied with any of these powers, by 1914 British policy had all but committed to declaring war on Germany if the latter attacked France. This was realized in 1914 when Germany invaded France via Belgium, whose neutrality had been guaranteed by London. The ensuing First World War pitted the Allied and Associated Powers including the British Empire, France, Russia, Italy and the U.S. against the Central Powers of Germany, Austria-Hungary and the Ottoman Empire. The war ended in an Allied victory in 1918 but inflicted a massive cost to British manpower, materiel and treasure.
Growing desire for Irish self-governance led to the Irish War of Independence, which resulted in British recognition of the Irish Free State in 1922. Although the Free State was explicitly governed under dominion status and thus was not a fully independent polity, as a dominion it was no longer part of the United Kingdom and ceased to be represented in the Westminster Parliament. Six northeastern counties in Ireland, which since 1920 were being governed under a more limited form of home rule, opted-out of joining the Free State and remained part of the Union. In light of these changes, the British state was renamed the United Kingdom of Great Britain and Northern Ireland on 12 April 1927 with the Royal and Parliamentary Titles Act. The modern-day United Kingdom is the same state, a direct continuation of what remained after the Irish Free State's secession, as opposed to being an entirely new successor state.
1801 to 1820
Union of Great Britain and Ireland
A brief period of limited independence for the Kingdom of Ireland came to an end following the Irish Rebellion of 1798, which occurred during the British war with revolutionary France. The Kingdom of Great Britain's fear of an independent Ireland siding against them with Revolutionary France resulted in the decision to unite the two countries. This was brought about by legislation in the parliaments of both kingdoms and came into effect on 1 January 1801. The Irish had been led to believe by the British that their loss of legislative independence would be compensated with Catholic emancipation, that is, by the removal of civil disabilities placed upon Roman Catholics in both Great Britain and Ireland. Despite personal sympathy for Roman Catholics, King George III believed that agreeing to Catholic Emancipation would violate his Coronation Oath to uphold the Protestant faith, and his lack of support for the initiative led the Prime Minister, William Pitt the Younger, to resign.Napoleonic Wars
During the War of the Second Coalition, Britain occupied most of the French and Dutch overseas possessions, the Netherlands having become a satellite state of France in 1796, but tropical diseases claimed the lives of over 40,000 troops. When the Treaty of Amiens ended the war, Britain agreed to return most of the territories it had seized. The peace settlement was in effect only a ceasefire, and Napoleon continued to provoke the British by attempting a trade embargo on the country and by occupying the city of Hanover, capital of the Electorate, a German-speaking duchy of the Holy Roman Empire which was in a personal union with the United Kingdom. In May 1803, war was declared again. Napoleon's plans to invade Great Britain failed, chiefly due to the inferiority of his navy, and in 1805 a Royal Navy fleet led by Nelson decisively defeated the French Imperial Navy and Royal Spanish Navy at Trafalgar, which was the last significant naval action of the Napoleonic Wars.In 1806, Napoleon issued the series of Berlin Decrees, which brought into effect the Continental System. This policy aimed to eliminate the threat from the British by closing French-controlled territory to foreign trade. The British Army remained a minimal threat to France; it maintained a standing strength of just 220,000 men at the height of the Napoleonic Wars, whereas the French Imperial Army exceeded a million men—in addition to the armies of numerous allies and several hundred thousand national guardsmen that Napoleon could draft into the French armies when they were needed. Although the Royal Navy effectively disrupted France's extra-continental trade—both by seizing and threatening French shipping and by seizing French colonial possessions—it could do nothing about France's trade with the major continental economies and posed little threat to French territory in Europe. France's population and agricultural capacity far outstripped that of the British Isles, but it was smaller in terms of industry, finance, mercantile marine and naval strength.
Napoleon expected that cutting Britain off from Continental Europe would end its economic hegemony. On the contrary Britain possessed the greatest industrial capacity in the world, and its mastery of the seas allowed it to build up considerable economic strength through trade to its possessions and the United States. The Spanish uprising in 1808 at last permitted Britain to gain a foothold on the Continent. The Duke of Wellington gradually pushed the French out of Spain, and in early 1814, as Napoleon was being driven back in the east by the Royal Prussian Army, the Imperial Austrian Army, and the Imperial Russian Army, Wellington invaded southern France. After Napoleon's surrender and exile to the Principality of Elba, peace appeared to have returned. Napoleon suddenly reappeared in 1815. The Allies united and the armies of Wellington and Gebhard Leberecht von Blücher defeated Napoleon once and for all at the Battle of Waterloo.
War of 1812 with the United States
To defeat France, Britain put heavy pressure on the United States, seizing merchant ships suspected of trading with France, and impressing sailors born in Britain, regardless of their claimed American citizenship. British government agents armed Indigenous American tribes in Canada that were raiding American settlements on the frontier. The Americans felt humiliated and demanded war to restore their honour, despite their complete unpreparedness. The War of 1812 was a minor sideshow to the British, but the American army performed very poorly, and was unable to successfully attack Canada. In 1813, the Americans took control of Lake Erie and thereby of western Ontario, knocking most of the Indian tribes out of the war. When Napoleon surrendered for the first time in 1814, three separate forces were sent to attack the Americans in upstate New York, along the Maryland coast, and up the Mississippi River to a massive defeat at the Battle of New Orleans. Each operation proved a failure with the British commanding generals killed or in disgrace. The war was a stalemate without purpose. A negotiated peace was reached at the end of 1814 that restored the prewar boundaries. British Canada celebrated its deliverance from American rule, Americans celebrated victory in a "second war of independence," and Britain celebrated its defeat of Napoleon. The treaty opened up two centuries of peace and open borders.Postwar reaction: 1815–1822
Britain emerged from the Napoleonic Wars a very different country than it had been in 1793. As the Industrial Revolution progressed, society changed, becoming more urban. The postwar period saw an economic slump, and poor harvests and inflation caused widespread social unrest. British leadership was intensely conservative, ever watchful of signs of revolutionary activity of the sort that had so deeply affected France. Historians have found very few signs, noting that social movements such as Methodism strongly encouraged conservative support for the political and social status quo.The major constitutional changes included a reform of Parliament, and a sharp decline in the power and prestige of the monarchy. The Prince regent, on becoming King George IV in 1820 asked Parliament to divorce his wife Queen Caroline of Brunswick so that he could marry his favourite lover. Public and elite opinion strongly favoured the Queen and ridiculed the king. The fiasco helped ruin the prestige of the monarchy and it recovered a fraction of the power wielded by King George III in his saner days. Historian Eugene Black says: