In the United Kingdom, the word liberalism can have any of several meanings. Scholars primarily use the term to refer to classical liberalism. The term can also mean economic liberalism, social liberalism or political liberalism. It can simply refer to the politics of the Liberal Democrats, a UK party formed from the merger of two centrist parties in 1988. Liberalism can occasionally have the imported American meaning; however, the derogatory connotation is much weaker in the UK than in the US, and social liberals from both the left and right wing continue to use liberal and illiberal to describe themselves and their opponents, respectively.

The Peelites were a breakaway political faction of the British Conservative Party from 1846 to 1859. Initially led by Robert Peel, the former Prime Minister and Conservative Party leader in 1846, the Peelites supported free trade whilst the bulk of the Conservative Party remained protectionist. The Peelites later merged with the Whigs and Radicals to form the Liberal Party in 1859.