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UK electoral systems - judgement grid

Every judgement on the grid, with the full evidence and named examples behind it. One card per row - open a card and read the case across all 6 columns.

First Past the Post

The UK's main plurality system: 650 single-member constituencies, one cross per voter, the candidate with the most votes wins. Used for House of Commons general elections, English local elections, and mayors and PCCs since 2024 (Elections Act 2022).

Proportional result [-]

Poorly: 2024 saw Labour win 33.7% of votes but 411 seats (63.2%) and a majority of 174.

FPTP delivers proportionality poorly. In 2024 Labour won 33.7% of the vote but 63.2% of seats (411) and a majority of 174, while Reform UK's 14.3% won 5 seats. Wasted votes and manufactured majorities are built in.

Strong single-party govt [+]

Well, usually: it normally produces single-party majority government, though 2010 and 2017 strained that.

FPTP normally delivers strong, stable single-party government able to carry out its manifesto and be held accountable. The pages note the strain on that promise: the 2010-15 coalition and the 2017 confidence and supply deal with the DUP show it can no longer guarantee single-party rule.

Voter choice [-]

Poorly: one cross only, and in safe seats the result is known in advance, driving tactical voting.

FPTP offers poor voter choice: one cross, and in safe seats a result known in advance. The 2019 mark scheme links this to discouraged turnout and tactical voting, where voters back a second choice to keep another party out.

MP-constituency link [+]

Well: relatively small single-member seats give every voter one clear, accessible local MP.

FPTP delivers a strong MP-constituency link. Relatively small single-member constituencies give every voter one clear, accessible representative, which the 2019 Pearson mark scheme lists as a key strength.

Simple for voters [+]

Well: one cross, few spoiled ballots and fast, clear results.

FPTP is simple for voters. The ballot is one cross, there are few spoiled papers and results come fast and clear, listed as a strength in the 2019 mark scheme.

Fair to small parties [-]

Poorly: it rewards concentrated support and punishes spread support (SNP 2.5% beat Reform's 14.3% on seats).

FPTP treats small parties poorly. It rewards concentrated support and punishes spread support: in 2024 the SNP's 2.5% won more seats (9) than Reform UK's 14.3% (5). The gate now blocks mass parties, not just extreme ones.

Additional Member System

A hybrid of FPTP and a closed party list. Each voter has two votes: one for a constituency member elected by FPTP, one for a regional party list. List top-up seats correct the disproportionality of the FPTP half. Used for the Scottish Parliament since 1999 and the Welsh Senedd 1999-2026.

Proportional result [+]

Well: the regional list top-up seats correct the disproportionality the FPTP half produces.

AMS delivers proportionality well. The list seats are top-up seats allocated to correct the disproportionality produced by the FPTP half, so the chamber as a whole comes closer to the overall vote share, and smaller parties win seats in line with support.

Strong single-party govt [-]

Poorly: coalition or minority government is the norm, with policy settled by post-election deals.

AMS delivers strong single-party government poorly. Coalition or minority government is the norm, with policy settled by post-election negotiation rather than by a single party's manifesto.

Voter choice [+]

Well: two votes that can be split between different parties.

AMS gives good voter choice. Each voter has two votes and can split them, backing one party for the constituency and another on the regional list.

MP-constituency link [±]

Partly: it keeps a local constituency member but creates two classes of member.

AMS keeps a local constituency member elected by FPTP, so the link survives, but it creates two classes of member, constituency and list, which weakens the clean single-MP link FPTP provides.

Simple for voters [±]

Partly: more complex than FPTP, with two votes and a closed list set by party leaders.

AMS is only partly simple. Voters cast two votes rather than one, and the closed list puts candidate order in the hands of party leaders, which adds complexity compared with a single cross.

Fair to small parties [+]

Well: top-up list seats let smaller parties win seats in line with their support.

AMS treats small parties well. The list top-up corrects the FPTP half, so chambers come closer to the vote share and smaller parties win seats in line with their support rather than being shut out.

Single Transferable Vote

A proportional system using multi-member constituencies. Voters rank candidates across and within parties; candidates are elected on reaching the Droop quota, with surplus and eliminated votes transferred until every seat is filled. Used for the Northern Ireland Assembly and Scottish council elections.

Proportional result [+]

Well: highly proportional, with very few wasted votes, which is why it suits power-sharing.

STV delivers proportionality well. It is highly proportional with very few wasted votes, and suits power-sharing, which is the reason it was chosen for Northern Ireland.

Strong single-party govt [-]

Poorly: coalition government is built in.

STV delivers strong single-party government poorly. Coalition government is built in, which in Northern Ireland takes the form of power-sharing rather than single-party majority rule.

Voter choice [+]

Well: the widest voter choice of any UK system, ranking candidates across and within parties.

STV gives the best voter choice of any UK system. Voters rank candidates 1, 2, 3 and so on, across parties and within them, even between candidates of the same party.

MP-constituency link [±]

Partly: every area still has members, but large multi-member seats dilute the single-MP link.

STV keeps representation for every area, but large multi-member constituencies dilute the single-MP link, so the clear one-representative connection FPTP provides is weakened.

Simple for voters [-]

Poorly: complex counts, with surplus and eliminated votes transferred on preferences.

STV is the least simple system here. The counts are complex: candidates are elected on the Droop quota, then surplus and eliminated votes transfer to next preferences until every seat is filled.

Fair to small parties [+]

Well: highly proportional, so smaller parties win seats in line with support.

STV treats small parties well. Because it is highly proportional with very few wasted votes, smaller parties win seats in line with their support rather than being shut out by concentration.

Supplementary Vote

A majoritarian system for single-winner posts. The voter marks a first and second choice; if no candidate has a majority of first choices, all but the top two are eliminated and second choices added on. Used for the Mayor of London and other mayors and PCCs until the Elections Act 2022 moved them to FPTP from 2024.

Proportional result [-]

Poorly: a majoritarian single-winner system, not designed to be proportional.

SV delivers proportionality poorly. It is a majoritarian system for single-winner posts such as mayors, so it elects one winner per contest rather than sharing seats in proportion to votes.

Strong single-party govt [+]

Well: it elects a single winner with a broader mandate than a plain plurality.

SV delivers a strong, clear single outcome. It elects one winner for a single post, and because second choices are added on, the winner has a broader mandate than a plain plurality.

Voter choice [±]

Partly: a first and second choice, but a second choice only counts if it is for one of the top two.

SV gives only partial voter choice. The voter marks a first and a second choice, but the second choice counts only if it is for one of the top two candidates, so a backed outsider's second preference is lost.

MP-constituency link [+]

Well: it elects one representative for a single post (a mayor or PCC), a clear single mandate.

SV gives a clear single mandate. It is used for single-winner posts such as the Mayor of London and PCCs, so each area or post has one clearly identified, directly elected representative.

Simple for voters [±]

Partly: more than one cross, and a second choice that only counts in limited cases.

SV is only partly simple. Voters mark a first and second choice rather than one cross, and the rule that a second choice counts only for the top two is harder to grasp than a plain plurality count.

Fair to small parties [-]

Poorly: a single-winner majoritarian system favours the leading candidates.

SV treats small parties poorly. As a single-winner majoritarian system it favours the two leading candidates, and a vote for a smaller candidate is unlikely to count beyond the first round.