Britain provides a prime example of the doctrine that international trade is the "engine of economic growth". Colonial trade had a significant impact on Britain's industrial development in the 17th and 18th centuries. "This triangular trade stimulated British industry in three ways. Transporting slaves traded for manufactured goods from England (and the East) to the plantations. There they produced sugar, cotton, indigo, molasses, and other tropical products. The processing of these products in England created new industries, and the maintenance of slaves and their owners provided another market for British industry. By 1750, everyone in England was engaged in trade. There was hardly a town that was not connected in one way or another with triangular trade or direct trade with the colonies. Profits were a major source of the capital accumulation necessary for Britain's Industrial Revolution. The capital accumulated from trade with the West Indies financed Watt and the invention of his steam engine.
The important role of foreign trade in Britain's industrialization can be measured by the following statistics. In 1688, British exports accounted for 5% of national income. A hundred years later, this figure had increased to 15%. By the early 1880s, exports accounted for 30% of national income. The rapid growth of export trade was the result of a new kind of trade that Britain was developing at the time: processing imported materials and exporting them into crystals. Before the 1750s, woolen goods accounted for half of the value of exports, and the market was mainly in southern Europe. During the trade boom of the 1780s, the main export was cotton goods, then metal goods, and the main market was first the American colonies, then India. Mandel 1l estimated that "between 1760 and 1780, the profits from India and the West Indies doubled, and these profits were invested in [British] industry as accumulated funds". British exports have led to the development of relevant industrial sectors in Britain. "At the end of the 17th century, Britain exported about 30 percent of its wool wool. By 1771 and 1772 this proportion had apparently risen to nearly half. The same trend could be seen in the cotton textile industry. E. J. Hobsbawn said, "The cotton industry, driven by colonial trade, flew like a glider."
From 1700 to 1800, Britain's export industry grew much faster than the rest of the economy. During the 100 years, export industry grew by 444%, while domestic industry and agriculture grew by only about 50% each. The export trade drives Britain. The development of the national economy is quite obvious. The expansion of overseas markets for British manufactured goods and the opening up of overseas sources of raw materials and food supplies were strategically important to all stages of Britain's industrialisation process. By the end of the 19th century, the British economy was heavily dependent on world markets. The growth rate of the British economy and its pattern are mostly shifted by the changes of supply and demand conditions in the world market.
