Great Britain was one of the major participants in the Seven Years' War, which in fact lasted nine years, between 1754 and 1763. British involvement in the conflict began in 1754 in what became known as the French and Indian War. However the warfare in the European theater involving countries other than Britain and France commenced in 1756. Britain emerged from the war as the world's leading colonial power, having gained all of New France in North America, ending France's role as a colonial power there. Following Spain's entry in the war in alliance with France in the third Family Compact, Britain captured the major Spanish ports of Havana, Cuba and Manila, in the Philippines in 1762, and agreed to return them in exchange for Spanish Florida. The Treaty of Paris in 1763 formally ended the conflict and Britain established itself as the world's pre-eminent naval power.

The Kingdom of Great Britain was a sovereign state in Western Europe from 1707 to the end of 1800. The state was created by the 1706 Treaty of Union and ratified by the Acts of Union 1707, which united the kingdoms of England and Scotland to form a single kingdom encompassing the whole island of Great Britain and its outlying islands, with the exception of the Isle of Man and the Channel Islands. The unitary state was governed by a single parliament at the Palace of Westminster, but distinct legal systems—English law and Scots law—remained in use.