Which laws protected British farming by charging duties on imported grain?

The Corn Laws were measures enforced in the United Kingdom between 1815 and 1846, which imposed restrictions and tariffs on imported grain. They were designed to keep grain prices high to favour domestic producers. The laws did indeed raise food prices and became the focus of opposition from urban groups who had far less political power than rural Britain. The Corn Laws imposed steep import duties, making it too expensive to import grain from abroad, even when food supplies were short. The laws were supported by Conservative landowners and opposed by Whig industrialists and workers. The Anti-Corn Law League was responsible for turning public and elite opinion against the laws, in a large, nationwide middle-class moral crusade with a Utopian vision.

"Corn" included any grain that requires grinding, especially wheat. The laws were introduced by the Importation Act 1815 (55 Geo. 3 c. 26) and repealed by the Importation Act 1846 (9 & 10 Vict. c. 22). The laws are often considered examples of British mercantilism.