In Britain until 1846, laws used to regulate the export or import of cereals in order to maintain an adequate supply for consumers and a secure price for producers. For centuries the Corn Laws formed an integral part of the mercantile system in England; they were repealed because they became an unwarranted tax on food and a hindrance to British exports.
Although mentioned as early as the 12th century, the Corn Laws only became significant in the late 18th century. After the Napoleonic wars, with mounting pressure from a growing urban population, the laws aroused strong opposition because of their tendency to drive up prices. They were modified 1828 and 1842 and, partly as a result of the Irish potato famine, repealed by prime minister Robert Peel 1846.