We use HISCLASS to code the occupational titles of over 30,000 English male workers according to the skill content of their work. We then track the evolution of the sampled working skills across three centuries of English history, from 1550 to 1850. We observe a modest rise in the share of ‘high-quality workmen’ deemed necessary by Mokyr and others to facilitate the Industrial Revolution, including machine erectors and operators. But we also find remarkable growth in the share of unskilled workers, rising from 20 % in the late sixteenth century to nearly 40 % in the early nineteenth century, caused mainly by falling shares of semi-skilled, blue-collar workers. Close inspection of the occupational structures within the main sectors of production suggests that deskilling occurred in agriculture and industry alike, prompted by land concentration in agriculture and workshop-to-factory changes in industry.