A Corn Law was first introduced in Britain in 1804, when the landowners, who dominated Parliament, sought to protect their profits by imposing a duty on imported corn. During the Napoleonic Wars it had not been possible to import corn from Europe. This led to an expansion of British wheat farming and to high bread prices.
Farmers feared that when the war came to an end in 1815, the importation of foreign corn would lower prices. This fear was justified and the price of corn reached fell from 126s. 6d. a quarter in 1812 to 65s. 7d. three years later. British landowners applied pressure on members of the House of Commons to take action to protect the profits of the farmers. Parliament responded by passing a law permitting the import of foreign wheat free of duty only when the domestic price reached 80 shillings per quarter (8 bushels). During the passing of this legislation, the Houses of Parliament had to be defended by armed troops against a large angry crowd.
This legislation was hated by the people living in Britain's fast-growing towns who had to pay these higher bread prices. The industrial classes saw the Corn Laws as an example of how Parliament passed legislation that favoured large landowners. The manufacturers in particular was concerned that the Corn Laws would result in a demand for higher wages.
There was a dreadful harvest in 1816. This caused bread prices to increase rapidly. This was followed by industrial unrest as workers demanded higher wages in order to pay for the increased food prices. As well as strikes there were food riots all over Britain.
The Corn Laws had an important political impact on Manchester. It was one of the main reasons why the group of middle-class moderate reformers began meeting at the home of John Potter. It also influenced working class radicals and the Corn Laws was one of the main issues that was to be addressed at the meeting that they had organised at St. Peter's Field on 16th August, 1819.