The new mass unenfranchised? Mapping unenfranchised adults and the case for residence-based voting in the UK

Universal suffrage is a defining feature of democracy. The UK electoral franchises, however, prohibit voting on the basis of some, but not all, nationalities. Residence-based voting involves allowing all adults who are legally resident in a country to vote. It has been introduced in Scotland and Wales for some elections. This article provides estimates of the number of unenfranchised adults in the UK. There has been an increase in the number of unenfranchised adults from 2.3 million in 2011 to 4.4 million in 2025. There are also 1.2 million unenfranchised adults in England and Northern Ireland. Unenfranchised adults tend to be concentrated in electoral constituencies in the UK, where they outnumber the number of votes cast for the sitting MP in 36 seats. If all residents could vote, 257 seats could have had a different outcome at the 2024 general election. This raises important political, constitutional and legitimacy questions about excluding those who contribute to society from the ballot box.