Proportional Representation
The nutshell
Proportional representation shares out seats to match the share of votes each party wins. A party that gets a third of the votes wins about a third of the seats.
Every fact on this page comes from official election rules and independent research. Each source tag — like IfG — opens where a fact comes from.
The basics
What it means
Proportional representation, often shortened to PR, is a way to turn votes into seats. It shares out the seats in a parliament to match the share of votes each party wins. A party with a third of the votes then wins close to a third of the seats.
Where the UK already uses it
The UK does not use one system for every election. The House of Commons is still chosen by First Past the Post, where the candidate with the most votes in an area wins.HoC Three other parliaments use more proportional systems: the Scottish Parliament, the Senedd in Wales, and the Northern Ireland Assembly.IfG
The main types
There is more than one kind of PR. In party-list PR, each voter picks a party, and seats are shared to match each party's votes. In the Single Transferable Vote, or STV, each voter ranks candidates in order, and each area elects several members.EC In the Additional Member System, or AMS, each voter gets two votes. One vote goes to a local candidate. The other goes to a party. Extra seats then top up the result so it better matches each party's vote share.IfG
What people say about it
Supporters, such as the Electoral Reform Society, argue that PR wastes fewer votes, because almost every vote helps elect someone.ERSOthers point out that one party rarely wins on its own. So parties more often have to share power in a coalition. A coalition is a government made of more than one party.IfG
- Seats can match votes more closely
- Fewer votes are wasted
- More parties can win seats
- One party rarely wins outright, so coalitions are common
- The link to one local MP can be weaker
- Some systems take longer to count
The deep end6 min
One country, several systems
The UK does not run every election the same way. The House of Commons Library records that, since 1997, several different voting systems have been used across the UK, while elections to the House of Commons still use First Past the Post.HoC
Three of the UK's parliaments now use a more proportional system. According to the Institute for Government, the Scottish Parliament uses the Additional Member System, the Northern Ireland Assembly uses the Single Transferable Vote, and the Senedd used a closed party-list system for its 2026 election.IfG
The three main types
Party-list PR asks each voter to choose a party. Seats are then shared out to match the share of votes each party won. A closed list means the party sets the order of its own candidates.
The Single Transferable Vote (STV) asks each voter to rank candidates in order of preference. Each area elects several members, not one. A candidate wins once enough votes are reached, and spare votes pass to the next choice. The Electoral Commission sets out how a Northern Ireland Assembly ballot is ranked and counted.EC
The Additional Member System (AMS) gives each voter two votes. One vote picks a local candidate. The other picks a party. Extra seats are added on top so the final result more closely matches each party's share of the party vote.
What supporters argue
The Electoral Reform Society, which campaigns to change the UK voting system to PR, argues that matching seats to votes means fewer votes are wasted, because almost every vote helps elect someone.ERS The Institute for Government, which takes no party's side, records that proportional systems produce results that match votes more closely than First Past the Post.IfG
What critics point to
The Institute for Government also notes that single-party majorities are rare under proportional systems, so coalitions and deals between parties are more common.IfG Supporters of First Past the Post value its single local MP for each area, and argue that systems with several members per area weaken that direct link. Some proportional systems, such as STV, also take longer to count, because votes are passed between candidates in rounds.