Final answer:
The British Empire expanded in the 17th and 18th centuries prompted by economic interests, trade, demand for land, and strategic military considerations. Conflicts arising from mercantilist policies and taxation without representation led to American independence. By the 20th century, the empire primarily dissolved as colonies gained independence.
Step-by-step explanation:
The British colonisation began in the early 1600s, with the British North American colonies being some of the earliest settlements that would eventually become populous and economically robust. Throughout the 1700s, Britain expanded its empire as a result of its victory in the Seven Years' War and its mercantile policies, such as the Navigation Acts. The empire was built on trade, with significant colonies established in India, the West Indies, and North America. Economic factors, trading imperatives, and the demand for land were common reasons prompting British expansion.
Colonial resentment towards British taxation and interference, such as the restrictions on westward expansion after the French and Indian War, catalysed the Thirteen Colonies' drive for independence, resulting in the American Revolution. Meanwhile, the British Empire continued to grow, with significant colonies in New Zealand, where the Treaty of Waitangi was signed in 1840, and in Australia, settled with convicts in the late 18th century. Various factors, including economic opportunities and strategic military interests, were driving forces for the British colonization efforts around the globe.
Additionally, the enforcement of British mercantilist policies provoked tensions with colonists, especially around economic restrictions and unfair taxation, which eventually led to the American Declaration of Independence in 1776. The British Empire at its height was an intricate complex of commerce, military might, and politics. However, by the late 20th century, most of the British colonies had gained independence, marking the end of the empire's global dominance.