It was John Campbell (Senior), Jock's great-great-grandfather, ship owner and merchant of Glasgow, who, towards the end of the 18th century, first established the fortunes of the Campbell family in the West Indies, through the slave trade. At the time, Glasgow trading houses, long-experienced in servicing the needs of North American slave plantations, were ready to capitalise on new opportunities in the sugar industry arising on the West Indies. By the 1780s they were supplying the two most important British exports to the West Indies, herring and coarse linen goods.