Rotten Borough

Rotten boroughs (also called "pocket boroughs" when controlled by a single patron) were English and, after 1707, British parliamentary constituencies whose electorates had shrunk to a handful of voters while they continued to send one or two Members to the House of Commons. The term became a byword for electoral corruption during the late 18th and early 19th centuries, when industrial cities such as Manchester and Birmingham had no direct representation while depopulated villages and even submerged sites returned MPs.

The classic examples are Old Sarum in Wiltshire, an uninhabited hill that returned two MPs with around seven eligible voters, and Dunwich in Suffolk, much of which had fallen into the North Sea. Gatton in Surrey reportedly had as few as two electors. Because the franchise in these boroughs was often vested in the owners of specific properties (so-called "burgage tenures"), seats could effectively be bought, sold, or inherited. Wealthy patrons used them to place allies, relatives, or themselves in Parliament; the elder William Pitt and Robert Walpole both entered the Commons through such seats.

Reform agitation grew through the late Georgian period, intensified by the 1819 Peterloo Massacre and the writings of radicals like William Cobbett. The Representation of the People Act 1832 (the "Great Reform Act"), passed under Earl Grey's Whig government, disenfranchised 56 rotten boroughs entirely, reduced another 31 to a single MP, and redistributed seats to growing urban centres. Subsequent reform acts in 1867 and 1884 continued the redistribution.

In contemporary political science, "rotten borough" is used analogically to describe any electoral district whose representation is grossly disproportionate to its population, or whose seat is treated as the personal property of a party or family. Comparativists invoke the term when analysing malapportionment in legislatures ranging from the pre-1962 U.S. state senates to modern upper houses with fixed regional quotas.