Rotten borough

The term rotten borough refers to boroughs (electoral districts) in the UK prior to the 1832 Reform Act which had minimal numbers of voters (the inhabitants were all never-enfranchised sheep, or the constituency was underwater, there being no permanently based submarine dwellings), but could be assigned at the will of the owner of the land.

Also known as a "pocket borough."

Its use has much declined since the abolition of most rotten boroughs. Most people probably only know it through the first episode of Blackadder The Third, where Blackadder makes use of a rotten borough to swing a vote in the Prince Regent's favour. Satirical and current affairs magazine Private Eye uses the term "Rotten Boroughs" as the title to one of its columns listing wrongdoings by local government powers in the UK.