Britain controlled about one-fourth of the Earth's land surface and one-fifth of the world's population in 1939. Fifty years later, its holdings outside the British Isles had become trivial, and it even faced an insurgency in Northern Ireland.
Britain spent the intervening years developing strategies to cope with what poet Rudyard Kipling called its "recessional," or the transient nature of Britain's imperial power. It has spent the last 20 years defining its place not in the world in general but between continental Europe and the United States in particular.
The Rise of Britain
Britain's rise to its once-extraordinary power represented an unintended gift from Napoleon. It had global ambitions before the Napoleonic Wars, but its defeat in North America and competition with other European navies meant Britain was by no means assured pre-eminence. In Napoleon's first phase, France eliminated navies that could have challenged the British navy. The defeat of the French fleet at Trafalgar and the ultimate French defeat at Waterloo then eliminated France as a significant naval challenger to Britain for several generations.
This gave Britain dominance in the North Atlantic, the key to global power in the 19th century that gave control over trade routes into the Indian and Pacific oceans.
This opportunity aligned with economic imperatives. Not only was Britain the dominant political and military power, it also was emerging as the leader in the Industrial Revolution then occurring in Europe. Napoleon's devastation of continental Europe, the collapse of French power and the underdevelopment of the United States gave Britain an advantage and an opportunity.
As a manufacturer, it needed raw materials available only abroad, markets to absorb British production and trade routes supported by strategically located supply stations. The British Empire was foremost a trading bloc. Britain resisted encroachment by integrating potential adversaries into trade relationships with the empire that they viewed as beneficial. In addition, the colonies, which saw the benefits of increased trade, would reinforce the defense of the empire.
As empires go, Britain resembled Rome rather than Nazi Germany. Though Rome imposed its will, key groups in colonial processions benefitted greatly from the relationship. Rome was thus as much an alliance as it was an empire. Nazi Germany, by contrast, had a purely exploitative relationship with subject countries as a result of war and ideology. Britain understood that its empire could be secured only through Roman-style alliances. Britain also benefitted from the Napoleonic Wars' having crippled most European powers. Britain was not under military pressure for most of the century, and was not forced into a singularly exploitative relationship with its empire to support its wars. It thus avoided Hitler's trap.
The German and U.S. Challenges
This began to change in the late 19th century with two major shifts. The first was German unification in 1871, an event that transformed the dynamics of Europe and the world. Once unified, Germany became the most dynamic economy in Europe. Britain had not had to compete for economic primacy since Waterloo, but Germany pressed Britain heavily, underselling British goods with its more efficient production.