James Irving, the son of an innkeeper from the Scottish border town of Langholm, built his career on the prodigious slave trade of late eighteenth-century Liverpool. As a ship's surgeon and then as a captain, he participated in the movement of slaves from West Africa to the Americas. This transatlantic trade, in which Portugal and France were Britain's chief competitors, accounted for the forced migration of over six million Africans in the eighteenth century alone. Of these men, women and children, almost two and a half million individuals, accounting for two-fifths of the total, were carried in British vessels. This British dominance of the slave trade was recognised in The West Indian Atlas of 1796, as the author commented that ‘every year about 72,000 slaves are carried from Africa to the West Indies. The Danes carry away about 3000, the Dutch 7000, the French 18,000, the Portuguese 8,000, the English have all the rest’.

Liverpool entered the slave trade in the opening years of the eighteenth century, sending out the ships the Liverpool Merchant and the Blessing in 1700. By the 1740s Liverpool had eclipsed its rivals Bristol and London, and the port consolidated its position as ‘the undisputed slaving capital of England and by far the largest slave port in the Atlantic world’. Between 1783 and 1792, a period broadly corresponding with Irving's career in the port, an average of 81 ships cleared annually from Liverpool compared with a combined annual average total of 36 from Bristol and London. In 1789, the year Irving was offered his first command, the tonnage of shipping engaged in the trade was 11,633 tons compared with 2,910 from London and 2,730 from Bristol. Liverpool's pre-eminence was still more apparent in the period between 1780 and the abolition of the trade in 1807, as it accounted for over three-quarters of British slave-ship clearances. The ‘remarkable business acumen’ of Liverpool merchants in exploiting opportunities in the Atlantic economy is one factor that has been used to explain Liverpool's ascendancy in the slave trade. Other significant factors included the investment in a dock and transport infrastructure, established patterns of trade with America and the West Indies, industrial expansion in Liverpool and its hinterland, and ‘an aggressive attitude towards realizing the political needs of a slave port’.