Voting systems in the UK

Current voting systems

Until 1997 nearly all elections in the Great Britain used the first-past-the-post (FPTP) voting system. Local and devolved elections in Northern Ireland used the single transferable vote (STV) system from the 1970s. University seats in the House of Commons also used STV from 1918 until their abolition in 1950.

Since 1997 several different voting systems have been introduced for different elections across the country.

Currently, FPTP is used for elections to the UK Parliament, including in Northern Ireland, and at all local elections in England and Wales. Mayoral elections in England and police and crime commissioner elections in England and Wales used the supplementary vote until 2023. From May 2023 the voting system was changed to FPTP by the Elections Act 2022.

Northern Ireland continues to use STV for local and Assembly elections. This system is a more proportional voting system than FPTP. Local elections in Scotland also use the STV system

Elections to the Scottish Parliament and to the London Assembly use a system known as the additional member system (AMS). This is designed to be more proportional and make the number of seats won by a party more closely reflect the share of the vote that party received. The Senedd Cymru used AMS up to and including its 2021 elections. Its next elections in May 2026 will use a closed list proportional system.

The types of electoral system used in the UK are summarised in the table below.

FPTP

FPTP is the current system for electing MPs to the House of Commons. The UK is divided into 650 separate constituencies, each of which elects a single Member of Parliament.

Winning candidates must receive more votes than any other candidate to be elected. They do not need an absolute majority of all votes cast (over 50%). 

FPTP is also used for local elections in England and Wales. In wards where two or three councillors are elected at the same time, the candidates that finish in the top two (or three as appropriate) are elected.

AMS

Voters have two ballot papers on polling day. One is used to elect a constituency member using FPTP.

The second is used to vote for a party. Parties are listed on a ballot paper and the voter places a cross next to the preferred political party. Several constituencies are grouped together to form a single region and a set number of people will be elected from that region’s list. Voters in each region will vote on the same regional list.

The votes for each part of the elections are counted separately.

The FPTP seats are counted first. Once the winner in each seat has been declared the votes in the regional list election can be counted.

The share of the vote in the regional list ballot is then used to allocate regional list seats. In calculating how many list seats a party is entitled to, FPTP constiteuncy seats already won are taken into account. This helps make the result more proportional.

STV

STV is a preferential voting system and operates in multi-member constituencies. Voters rank candidates in order of preference by marking 1, 2, 3 etc against the candidates’ names on the ballot paper. Voters can rank candidates within parties or across different parties.

Candidates must obtain a certain quota of votes in order to be elected. If they exceed the quota their suplus votes are reallocated. If no candidate reaches the quota, the lowest candidate is eliminated and their votes are reallocated based on second, third, and so on preferences. This process continues until all seats have been filled.

Closed list proportional

Voters in a multi-member constituency vote for a party rather than a candidate. The party lists their candidates in order on the ballot paper. Seats are allocated in proportion to the number of votes received. If a party wins two seats, the top two candidates on their list is elected. Independents can also stand and they are effectively a list of one.

AV

AV is also a preferential voting system. Under the AV system, voters are entitled to rank candidates in their order of preference, marking 1, 2, 3 etc against the candidates’ names on the ballot paper. In an AV election only one candidate wins but must poll over 50% of the vote.

If a candidate fails to gain 50% of the vote on the first count, the lowest candidate is eliminated and their second preferences are reallocated. This reallocation of the bottom candidate’s votes – based on second, third and fourth preferences etc – continues until one candidate gains more than 50%.