supported by George III. The result was that "in consequence of the British conquests and under the shelter of the British flag, the slave trade became more active than ever," and that under Pitt the English slave trade "more than doubled."
A considerable number of statistics are available from various sources covering the activities of the trade during the 18th Century and the closing years of the 17th, which give some idea of the stupendous havoc wrought in Africa—almost entirely Western Africa—during that period. The following have been selected from the most reliable authors, but they are only approximately consecutive;
| 1666–1766. | — | Number of slaves imported by the British alone into British, French and Spanish American Colonies–three millions (quarter of a million died on the voyage). |
| 1680–1786. | — | Slaves imported into the British American Colonies–2,130,000, Jamaica alone absorbing 610,000. |
| 1716–1756. | — | An average of 70,000 slaves per annum imported into all the American Colonies, or a total of 3,500,000. |
| 1752–1762. | — | Jamaica alone imported 71,115 slaves. |
| 1759–1762. | — | Guadeloupe alone imported 40,000 slaves. |
| 1776–1800. | — | An average of 74,000 slaves per annum imported into all the American Colonies, or a total of 1,850,000. (Annual average: by British 38,000; Portuguese, 10,000; Dutch, 4.000; French, 20,000; Danes, 2,000.) |
Some notion can be formed of the profits of the trade by taking selected cases. From about 1730, Liverpool began for various reasons to eclipse both London and Bristol as the chief English centre of the trade. In the eleven years, 1783–1793, 921 Liverpool ships were employed in the convoying of slaves. They carried 303,737 slaves of the total value of £15,186,850. After deducting 15 per cent, under divers heads, the net return to Liverpool in those eleven years amounted to £12,294,116, or an average of £1,117,647 per annum. The net profit to those actually engaged in the trade was £2,361,455 6s. 1d., or an average of £214,677 15s. 1d. per annum.
There was, of course, a double profit upon the value of the slave when sold in the West Indies, and upon articles of British manufacture—largely cotton goods—disposed of in Africa for the slave's purchase: Manchester merchants largely profited from the latter. It is computed that from 1750 to 1800, one-fourth of the ships
