The Corn Laws were introduced in 1815 in Britain, in order to protect the British agricultural sector after a series of grain shortages during the Napoleonic wars. According to these laws, foreign corn could be imported only when the domestic price rose above 80 shillings/quarter. While this legislation benefited landlords, the dominant force in the British parliament, it harmed manufacturers and workers. As the cost of food increased, people spent less and less on other commodities, such as manufactured goods. Manufacturers, traders, bankers, and capitalists united in the Anti-Corn-Law League in 1838 to pressure the parliament to repeal the Corn Laws. As part of the Anti-Corn-Law campaign, James Wilson, a Scottish member of the League, founded The Economist magazine in 1843.
In 1846 Prime Minister Robert Peel repealed the Corn Laws, ushering in an era of increased economic integration. This openness in the structure of international trade only lasted until 1880, as Britain’s hegemonic power decreased and led to a period of relative closure.
It is debated whether the repeal of Corn Laws was influenced by ideas, institutions or domestic interests. Douglas Irwin argues for the importance of ideas, pointing to statements made by Robert Peel well before repeal in which the Prime Minister regularly expressed his belief in free trade but insisted that the protection of agriculture was a justified exception. Later, Irwin states that Peel changed his views on agricultural protection, justifying his shift in opinion by claiming that he had learned from experience and observation the harm done to the British economy by the Corn Laws. Cheryl Schonhardt-Bailey, on the other hand, stresses the importance of domestic interests. She argues that pressure groups for free trade and the Anti-Corn-Law League ultimately influenced Robert Peel and other elements in Parliament to support repeal. She explains that Peel appealed to his Conservative Party's base, landed elites, by arguing that repeal would actually maintain the status quo by preventing a class between the upper class and those who were harmed by the Corn Laws. In this way both interest groups affected the policy, and the way in which is was passed in Parliament. 
- http://www.britannica.com/EBchecked/topic/137814/Corn-Law 09/24/2010
- Irwin, Douglas A. “Political Economy and Peel’s Repeal of the Corn Laws.” Economics and Politics 1, no. 1 (1989): 41-59.
- Schonhardt-Bailey, Cheryl. From the Corn Laws to Free Trade: Ideas, Interests, and Institutions in Historical Perspective. Cambridge, MA: MIT Press, 2006. Ch 2