From the 1820s the Industrial Revolution was in full swing in Scotland, linked (in a way historians have not altogether disentangled) to a dramatic increase in population. There were perhaps a million people in Scotland at the beginning of the 18th century. By the beginning of the 19th century there were more than 1.5 million, and by the turn of the 20th century the population exceeded 4.5 million. The manufacturing towns showed spectacular increases. Hundreds of thousands of Irish emigrants went to Scotland in the 19th century, beginning prior to but increasing in number during the Irish Potato Famine of 1845–49. In some country regions there was a population decrease as people moved to the towns, to England, or overseas. Part of the overall increase was the result of improved medical care that had lessened the ravages of epidemic diseases by the mid-19th century. Much of the food for the increased population was supplied by progressive Scottish agriculture. Farming in the southeast was celebrated for its efficiency in the early 19th century, and the northeast became famous for its beef cattle and Ayrshire for its milking herds.

The key advance was in heavy industry, which from about 1830 took the industrial primacy from textiles, at a time when industry as a whole had replaced agriculture as Scotland’s chief concern. Coal production rose, as did that of iron, with the hot-blast process (1828) of James Beaumont Neilson making Scottish ores cheaper to work. Major canals, such as the Forth and Clyde, completed in 1790, enjoyed a short boom before being rendered obsolete by the railways, of which the Glasgow-to-Garnkirk (1831) was noteworthy for using steam locomotives (rather than horses) from its inception. Above all, Scottish international trade was catered to, and Clydeside’s reputation made, by the building of ships. Robert Napier was the greatest of many great Scottish marine engineers. The later 19th century was characterized by the expansion of new heavy industry, such as steel, and technological advances in shipbuilding and marine engineering.

Politics and religion

Parliamentary (1832) and burgh (1833) reform ended fictitious county votes and corrupt burgh caucuses but disillusioned the working classes by failing to extend to them the franchise. As in England, they had to await the 1867 and subsequent Reform Acts (see Reform Bill). But the great bulk of the Scottish middle classes were delighted with the Whigs, who had brought the reforms. The Whig Party, or Liberal Party (as it became known in the 1860s), dominated Scottish mid-19th-century politics. Liberal Party leader and hero William Ewart Gladstone, of Scottish parentage, was widely admired among Scots for his moral dynamism and fire despite his High Church Episcopalianism.

Ecclesiastical strife was perhaps more important than parliamentary politics in Scottish life in the 19th century. Opposing approaches to the relationship between church and state within the Church of Scotland brought about the Ten Years’ Conflict, which was not resolved until a large proportion of the clergy and the laity left the established Church of Scotland in 1843 to form the Free Church of Scotland. This fracture was not healed until the Presbyterian reunion in 1929, and it had profound effects on Scottish life, because the church was the main agency of social welfare (until 1845) under the old Poor Law of Scotland and undertook a similar role in the Scottish education system until 1872.

Trade unions of skilled workers had led an uninterrupted existence since the early 19th century. By the 1880s unskilled workers were being organized. Various factors delayed the permanent organization of the miners until a major leader, James Keir Hardie, emerged from their ranks. Failing to sufficiently engage the Liberals in support of organized labour, he helped form the Scottish Labour Party in 1888. In 1893 Hardie created the Independent Labour Party (ILP) for Britain as a whole, and in 1900 the ILP federated with the trade unions for the purpose of running the Labour Party (given its present name in 1906). However, liberalism continued to dominate Scottish politics until 1922 (the Liberals even won a majority of Scottish seats in the two general elections of 1910), as the labour movement, despite the activity of Hardie, found it difficult to emerge from the shadow of the Liberals.