The term rotten borough came into use in the eighteenth century, and was used to mean a parliamentary borough with a tiny electorate, so small that voters were susceptible to control in a variety of ways. The word “rotten” had the connotation of corruption as well as that of long-term decline.
Typically, rotten boroughs had gained their representation in parliament when they were more flourishing centres, but the borough’s boundaries had never been updated, or else they had become depopulated or even deserted over the centuries. Some had once been important places or had played a major role in England’s history, but had fallen into insignificance as for example industry moved away.
For example, in the 12th century Old Sarum had been a busy “city” reliant on the wealth expended by its ownSarum Cathedral within its city precincts, but it was abandoned when the present Salisbury Cathedral (also called “New Sarum”) was founded nearby on a new site, which immediately attracted merchants and workers who built up a new town around it. Despite this dramatic loss of population, the borough of Old Sarum retained its right to elect two members of parliament.
Many such rotten boroughs were controlled by landowners who gave the seats in parliament to their politically like-minded friends or relations, or even went to parliament themselves. Commonly they sold them for money or other favours; the peers who controlled such boroughs had a double influence in Parliament as they themselves held seats in the House of Lords.
Examples of rotten boroughs include the following:
Old Sarum in Wiltshire had 3 houses and 7 voters
Gatton in Surrey had 23 houses and 7 voters
Newtown on the Isle of Wight had 14 houses and 23 voters
East Looe in Cornwall had 167 houses and 38 voters
Dunwich in Suffolk had 44 houses and 32 voters (most of this formerly prosperous town having fallen into the sea)
Plympton Erle in Devon had 182 houses and 40 voters. One seat was controlled from the mid-17th century to 1832 by the Treby family of Plympton House.
Bramber in West Sussex had 35 houses and 20 voters
Callington in Cornwall had 225 houses and 42 voters. A pocket borough of the Rolle family of Heanton Satchville and Stevenstone in Devon.