rotten borough
noun British historical
A borough that was able to elect an MP despite having very few voters, the choice of MP typically being in the hands of one person or family.The city's convoluted electoral system is riddled with rotten boroughs, giving some corporate voters 4,000 times more punch than the votes of ordinary citizens....
- The Reform Bill of 1832 redistributed seats from rotten boroughs to populous towns and counties and increased the electorate from 478,000 to 814,000.
- It works well in Scotland and now, with PR for Scottish local elections, it breaks up the old Labour rotten boroughs.
Origin
So named because the borough was found to have ‘decayed’ to the point of no longer having a constituency.