By 1800 the Highlands had become overpopulated relative to the means of subsistence. Many lairds, seeking to support their tenantry through the kelp industry, were ruined when it collapsed in the period from 1815 to 1825. Other landowners introduced sheep, sometimes violently removing their tenants in the “Highland Clearances”—as agents of the Sutherland family did in Strathnaver, Sutherland, about 1810–20. The Potato Famine in the Scottish Highlands that began in the mid-1840s caused distress and encouraged landowners to engage in a new round of clearances and to sponsor large-scale emigration.

By the 1880s Highland subsistence-farming tenants, or “crofters,” faced a new problem. Deer forests had replaced sheep runs as the most immediately profitable land use open to landowners, and, as a result, the shortage of land for grazing and arable agriculture was the major grievance of the crofting community. Parliamentary agitation by the crofters, who voted for the first time in 1885, and by their Lowland sympathizers, as well as sporadic outbursts of violence beginning in 1882 (the “Crofters’ War”), secured an act of 1886 that gave the crofters security of tenure and empowered a Crofters’ Commission to fix fair rents, though it did little to make more land available to crofters. (Further legislation in 1911 and 1919 helped to alleviate this problem.) Unlike their Irish counterparts, the Highlanders sought not ownership of their land but the imposition of certain standards of conduct and responsibility upon their landlords. As the crofting agitation of the 1880s united both Highlanders and Lowlanders, it was a key stage in the forging of a modern Scottish consciousness.

World War I and after

World War I had a great effect on Scottish society; 74,000 Scots were killed and industry mobilized as never before in a coordinated national effort. Clyde shipbuilding and engineering were crucial, and Clydeside was the key munitions centre in Britain. In retrospect, however, the expansion of heavy industry in the 1920s was in fact an overexpansion. The collapse of the wartime boom in 1920 began a period of economic depression in Britain, in which Scotland was one of the worst-affected regions.

Economic distress bred political radicalism. The Liberals were eclipsed, and in most seats the real contest was between the Unionists and Labour, which became Scotland’s biggest single party for the first time in the election of 1922. Willie Gallacher, Scotland’s only notable communist member of Parliament and an able political theorist strongly influenced by Vladimir Lenin, was at the same time a radical belonging to a revered Scots tradition. In 1930 John Wheatley, who had been minister of health in the first Labour government (1924) and the author of an important housing act, died, thereby depriving left-wingers in the Labour Party of a skilled leader, and counsels of moderation in the party prevented its taking any distinctive initiative on the economic crisis. Ramsay MacDonald, a Scot who had led two minority Labour governments, agreed to form a national coalition government with Conservative and Liberal support in 1931. However, the Labour Party refused to participate, disowned MacDonald, and was heavily defeated at the polls in Scotland as elsewhere.

Another political development that resulted partly from economic distress was the formation in 1934 of the Scottish National Party (SNP), a merger of two previous parties. It had some distinguished supporters, especially literary figures, but it was suspected, sometimes unfairly, of political extremism and made little electoral impact before World War II. The national government of the 1930s was dominated by the Conservatives. While opposed to an independent Scottish legislature, this government furthered the extension of the Scottish administrative system in 1939, installing it in St. Andrew’s House in Edinburgh.

The interwar period was one of significant cultural advance and self-confidence in Scotland. In poetry the dominant figure in this renaissance was Christopher Murray Grieve, who published under the pseudonym Hugh MacDiarmid. Important achievements in prose literature were made by Neil Gunn, Edwin Muir, Nan Shepherd, and Willa Muir. James Leslie Mitchell (Lewis Grassic Gibbon) published a trilogy of novels, collectively known as A Scots Quair (1932–34), which charted the changes in the social life of the communities of northeastern Scotland. In Gaelic literature poetry continued to be the dominant form, and the lyrical work of Somhairle MacGill-eain (Sorley Maclean) dominated the 20th-century scene.