Electoral Systems: Plurality/Majoritarian versus Proportional Representation
1. Introduction and key terminology
An electoral system is the mechanism by which votes cast in an election are converted into seats (or, in some cases, a single office). The choice of system is not a neutral technical matter: it shapes which parties can realistically win power, how governments are formed, how voters behave, and how fairly the outcome reflects the wishes of the electorate. This is one of the most heavily contested areas of UK Politics, and it rewards precise use of terminology, so it is worth clarifying some distinctions before going further.
Plurality systems award victory to whichever candidate or party gets the most votes, even if that is well short of 50%. The UK’s First Past the Post (FPTP) system is a plurality system, not strictly a majoritarian one, although it is conventionally grouped with majoritarian systems in most textbooks because both families share a common effect: they tend to manufacture a clear winner rather than mirror the electorate proportionally.
Majoritarian systems require a candidate to secure an absolute majority (50%+1) of votes to win, which usually involves either a second round of voting (the two-round system used in French presidential elections) or a preferential ballot with elimination rounds (the Alternative Vote, AV). The UK does not currently use a true majoritarian system for any major election, though AV was put to a national referendum in 2011.
Proportional representation (PR) systems aim to allocate seats to parties in close proportion to their share of the vote. There is no single PR system; the family includes list PR, the Single Transferable Vote (STV), and hybrid/mixed systems such as the Additional Member System (AMS), also known internationally as Mixed Member Proportional (MMP).
This analysis treats “pluralistic/majoritarian” systems together, since that is how they are usually discussed in comparative terms (as systems that prioritise decisive outcomes over proportionality), while noting where the plurality/majoritarian distinction actually matters.
2. Plurality and majoritarian systems
First Past the Post (FPTP): mechanics
FPTP is used for UK general elections (electing MPs to the House of Commons) and for most English and Welsh local council elections. The mechanics are simple:
- The country is divided into 650 single-member constituencies.
- Voters mark a single “X” against one candidate.
- The candidate with the most votes in each constituency wins, regardless of whether they secured 50% of the vote.
- The party that wins the most seats overall (not necessarily the most votes) typically forms the government, either alone with a majority or, if no party reaches 326 seats, through coalition or confidence-and-supply arrangements (as with the Conservative-Lib Dem coalition of 2010, or the Conservative-DUP confidence-and-supply deal of 2017).
Effects of FPTP
Disproportionality between votes and seats. This is the most consistent and heavily criticised feature of FPTP. The 2024 general election is a stark recent illustration:
| Party | Vote share | Seats won | Seat share |
| Labour | 33.7% | 411 | 63.2% |
| Conservative | 23.7% | 121 | 18.6% |
| Reform UK | 14.3% | 5 | 0.8% |
| Liberal Democrat | 12.2% | 72 | 11.1% |
| Green | 6.7% | 4 | 0.6% |
| SNP | 2.5% (UK-wide) | 9 | 1.4% |
Labour won a landslide majority of 174 seats on barely a third of the national vote, while Reform UK, with almost 4.1 million votes (more than the SNP, Greens and several other parties combined), won only five seats. The House of Commons Library and other analysts described this as the most disproportionate result on record, illustrating how FPTP can produce a “landslide from a minority” and simultaneously exclude a party with substantial but geographically dispersed support.
Manufactured majorities. FPTP tends to reward the largest party with a bonus in seats beyond its vote share, because winning narrowly in many constituencies accumulates seats efficiently, while coming a close second everywhere yields nothing. This is precisely what benefited Labour in 2024 and, in reverse, previously helped the Conservatives secure comfortable majorities on vote shares in the low-to-mid 40s (as in 2019, when 43.6% of the vote produced 56.2% of seats).
Two-party dominance (Duverger’s Law). The political scientist Maurice Duverger observed that plurality systems tend to squeeze the party system down to two dominant parties, because voters and donors gravitate towards whichever of the two front-runners is more likely to defeat the party they dislike most, rather than “wasting” support on a third option. This has historically held in the UK, with Labour and the Conservatives dominating government since 1935, although the 2024 result (with Reform, the Greens and the Liberal Democrats all achieving significant vote shares) has renewed debate about whether this pattern is weakening.
Wasted votes and safe seats. Votes cast for a losing candidate, and votes cast above the winning margin for the successful candidate, are often described as “wasted” because they do not affect the outcome. Many UK constituencies are “safe seats” that have not changed hands for decades, which critics argue depresses turnout and reduces the incentive for parties to campaign nationally, concentrating effort instead on a shrinking number of marginal seats.
Tactical voting. Because votes for smaller parties can appear futile in a given constituency, voters often vote tactically for their preferred candidate among the two most likely winners, rather than expressing a sincere first preference. This distorts the apparent level of support for smaller parties and makes the system harder to interpret as a clear expression of public opinion.
Geographic concentration versus dispersal. FPTP rewards parties whose support is geographically concentrated (the SNP in Scotland, the Liberal Democrats in their target seats after refining their 2024 strategy) and punishes parties whose support is spread evenly across the country (Reform UK and the Greens in 2024).
Strong, stable, accountable government. The case in favour of FPTP rests heavily on the government it tends to produce. A single party with a working majority can govern without needing to negotiate its programme with coalition partners, and voters know clearly who to reward or blame at the next election. This is often summarised as the trade-off between proportionality and governability: FPTP sacrifices the former for the latter, at least in normal circumstances (though the hung parliaments of 2010 and 2017 show it does not always deliver single-party majorities).
Strong constituency link. Each MP represents a single, identifiable geographic constituency, which supporters of FPTP argue strengthens accountability and gives constituents a clear, named representative to approach.
Other majoritarian variants (comparative)
- Two-round system (France): if no candidate wins an absolute majority in the first round, a run-off is held between the top candidates (typically the top two, though French rules allow more). This guarantees the eventual winner has majority support among those who vote in the final round, at the cost of requiring voters to return to the polls.
- Alternative Vote (AV): voters rank candidates in order of preference; if no one wins an outright majority of first preferences, the lowest-placed candidate is eliminated and their votes redistributed according to second preferences, repeating until one candidate has a majority. AV was rejected by 67.9% to 32.1% in the UK’s 2011 referendum, on a turnout of 42%, following a campaign in which opponents (including senior Conservatives) characterised it as complex and unfair, while proponents (including the Liberal Democrats, who had secured the referendum as a condition of coalition) argued it would reduce wasted votes. Its rejection significantly set back the electoral reform movement in the UK.
- Supplementary Vote (SV): a simplified two-preference version of AV, used in England for mayoral and police and crime commissioner elections until 2022, when the government reverted these elections to FPTP via the Elections Act 2022, a move critics argued reduced voter choice and disproportionately benefited larger parties in these contests.
3. Proportional representation systems
List PR
Under list PR, parties publish a ranked list of candidates for each region or for the country as a whole, and seats are allocated to parties in proportion to their vote share, with the top names on each list taking the seats won. In closed list systems, voters can only choose a party, and the party determines who fills the seats; in open list systems, voters can also indicate a preference for individual candidates within a party’s list, affecting which of that party’s candidates are elected.
The UK used a closed regional list system for European Parliament elections between 1999 and its departure from the EU. List PR is used nationally in the Netherlands (in its purest, near-perfectly proportional form, with a very low effective threshold) and in Israel, both of which regularly produce highly fragmented, multi-party parliaments and coalition governments.
Single Transferable Vote (STV)
STV uses multi-member constituencies (typically returning between three and six MPs/MSPs/councillors). Voters rank candidates in order of preference. A quota is calculated (the minimum number of votes needed to guarantee election, given the number of seats available), and candidates who exceed the quota on first preferences are elected, with their surplus votes redistributed according to next preferences; if no candidate reaches the quota, the lowest-placed candidate is eliminated and their votes redistributed, and the process repeats until all seats are filled.
STV is used for elections to the Northern Ireland Assembly, for local government elections in Scotland and Northern Ireland, and nationally in the Republic of Ireland. It is generally regarded by electoral reformers as one of the most proportional and voter-friendly systems, since it combines proportionality with a genuine choice between candidates (including from within the same party) and preserves a form of constituency link, albeit to a group of MPs/MSPs rather than one.
Additional Member System (AMS) / Mixed Member Proportional (MMP)
AMS is a hybrid system combining constituency MPs elected by FPTP with additional “top-up” members elected from regional party lists, with the top-up seats allocated to correct the disproportionality produced by the constituency results, so that each party’s overall seat total more closely reflects its vote share. Voters typically cast two votes: one for a constituency candidate and one for a regional party list.
AMS is used for elections to the Scottish Parliament and the London Assembly (the Welsh Senedd used AMS from 1999 to 2021 but has since moved to closed list PR, discussed below). Germany uses a similar system (Mixed Member Proportional) for the Bundestag, where the top-up mechanism is calibrated to produce close-to-perfect overall proportionality, subject to a 5% national vote threshold designed to keep very small or extremist parties out of parliament, a feature widely credited (rightly or wrongly) with contributing to the postwar stability of German coalition politics.
Effects of PR systems
Greater proportionality. By design, PR systems reduce the gap between a party’s vote share and its seat share. Scottish Parliament results under AMS have historically been far closer to proportional than Westminster results under FPTP for the same electorate, though AMS is only semi-proportional, since the constituency component still tends to favour larger parties before the list seats correct for this.
Multi-party systems and coalition or minority government. PR tends to allow smaller parties to win seats roughly in line with their support, which fosters multi-party systems and makes single-party majorities less common.
The Scottish Parliament has been governed by coalition (Labour-Lib Dem, 1999-2007) and minority SNP government for extended periods; the Senedd has similarly required coalition or cooperation agreements.
This is often framed as either a strength (better reflecting a genuinely pluralistic society, forcing consensus-building) or a weakness (producing weaker, less decisive government and post-election deals that voters did not directly choose).
Fewer wasted votes. Because seats are allocated more closely to vote share, PR systems reduce (though rarely eliminate entirely) the sense that voting for a smaller party is pointless, which some argue increases turnout and reduces tactical voting.
Weaker constituency link (in list systems). Pure list PR, especially at a national rather than regional level, can sever the direct link between a representative and a specific geographic area, which critics see as reducing accountability. STV and AMS mitigate this to varying degrees.
Complexity. PR systems, particularly STV with its quota calculations and multiple counting rounds, are less immediately intuitive to voters than simply marking an “X”, which was a significant line of attack during the 2011 AV referendum even though AV itself is not a PR system.
Risk of extremist or single-issue party representation. Lower effective thresholds can allow small, sometimes fringe, parties into parliament, which is why systems such as Germany’s impose a minimum vote threshold (5%) before a party qualifies for list seats.
The UK’s mixed electoral landscape
One of the most useful points for evaluation is that the UK does not use a single electoral system consistently across its own institutions, which provides a built-in natural comparison:
- Westminster general elections: FPTP
- Scottish Parliament: AMS
- Welsh Senedd: used AMS from 1999 to 2021, but following the Senedd Cymru (Members and Elections) Act 2024, the Senedd moved to a closed list PR system, first used at the May 2026 election. The Senedd was also enlarged to 96 members, elected across 16 constituencies each returning six Members, with seats allocated by the D’Hondt formula. Wales no longer uses AMS at all; every Member is now elected by closed list PR
- Northern Ireland Assembly: STV
- London Assembly: AMS (as of 2024, elected via the Additional Member System, after a change from the previous supplementary vote/list hybrid used for the mayoralty and a separate list system used for the Assembly)
- London Mayor and other directly elected mayors, and Police and Crime Commissioners: reverted from Supplementary Vote to FPTP in 2022
- Local council elections: FPTP in England, STV in Scotland, a mix in Northern Ireland
This patchwork means students of UK Politics can compare, within a single political system, how the same voters, the same party system, and broadly the same political culture produce different outcomes and different governing arrangements under different electoral rules, which is a genuinely useful natural experiment for evaluation essays.
Case study: the 2026 Senedd election under closed list PR
The May 2026 Senedd election is a useful, up-to-date illustration of closed list PR in practice, and offers a direct contrast with the 2024 Westminster result discussed above. Plaid Cymru became the largest party for the first time since devolution began, winning 43 seats on 35.4% of the vote, with Reform UK entering the Senedd for the first time and becoming the second-largest party with 34 seats on 29.3% of the vote. Welsh Labour fell to third place with just nine seats, the first time Labour has not been the largest party in a Senedd election, while the Conservatives won seven seats, the Greens two, and the Liberal Democrats one.
The Electoral Reform Society’s proportionality analysis, using the Loosemore-Hanby disproportionality (DV) measure (where a lower score indicates a more proportional result), calculated a DV score of 15.5 for the 2026 Senedd result, broadly in line with the average across previous Senedd elections.
By contrast, the equivalent Westminster result in Wales at the 2024 general election produced a DV score of 47.4, against a longer-run Welsh average of 29.3 for general elections. The over-representation of the largest party (Plaid Cymru) was just 9.4 percentage points above its vote share, the lowest over-representation figure of any Senedd election to date, and the first time it has fallen below 10 points.
This gives a concrete, current figure to cite when arguing that PR systems narrow the gap between vote share and seat share relative to FPTP, while the closed list format still drew criticism, including from the Electoral Reform Society itself, for giving voters no ability to choose between individual candidates within a party’s list.
5. Comparative example: the United States
The USA offers a useful contrast because it combines plurality elements with features that are majoritarian in effect but structured very differently from anything in the UK.
The House of Representatives is elected via single-member plurality districts, functionally very similar to FPTP, and shares many of the same effects: a strongly entrenched two-party system (arguably even more rigid than the UK’s, since minor parties almost never win federal seats), and significant distortion caused by the drawing of district boundaries.
Gerrymandering, the deliberate manipulation of district boundaries by state legislatures to advantage one party, is a distinctly American aggravation of the disproportionality problem inherent in plurality systems, and has become a major and recurring subject of litigation and political controversy.
The Senate is not proportional to population at all: each state receives two senators regardless of population, meaning California (around 39 million people) has the same representation as Wyoming (around 580,000).
This is a deliberate design feature of federalism rather than a proportionality failure, but it is often cited alongside the House and the Electoral College as evidence of a broader tension in the US system between majoritarian principles and structural protections for smaller states.
The Electoral College, which formally elects the President, is a state-based, largely winner-takes-all system: in 48 of 50 states (Maine and Nebraska allocate some electors by congressional district), all of a state’s electoral votes go to whichever candidate wins the statewide popular vote, however narrow the margin.
This can and has produced a president who lost the national popular vote, most notably George W. Bush in 2000 and Donald Trump in 2016. This is arguably a more extreme distortion than anything produced by UK FPTP, since it can invert the national result entirely rather than merely exaggerate the winning margin, and it channels the entire presidential campaign into a small number of competitive “swing states” while most of the country is barely contested.
Comparing the UK and US cases together illustrates that plurality/majoritarian logic produces broadly similar effects (two-party dominance, safe versus competitive seats, disproportionality) wherever it is applied, but the severity and specific character of those effects depends heavily on the surrounding institutional design, such as how district boundaries are drawn and controlled, and whether the system operates at a single national level or is layered on top of a federal structure.
Evaluating the systems: a comparative framework
A-level mark schemes reward evaluation against explicit criteria rather than simple description. Useful criteria include:
| Criterion | FPTP / majoritarian systems | PR systems |
| Proportionality of votes to seats | Weak; can produce landslide majorities from a minority of the vote | Strong (varies by type; list PR strongest, AMS semi-proportional) |
| Government stability/decisiveness | Usually strong, single-party majorities more likely | Weaker; coalition or minority government more common |
| Voter choice | Limited to one “X”; little intra-party choice | Greater under STV and open list; limited under closed list |
| Simplicity for voters | Very simple | Varies; STV and list systems more complex than FPTP |
| Constituency accountability | Strong, single named MP | Varies; strong under STV/AMS, weak under national list PR |
| Representation of smaller/minor parties | Poor | Good, subject to any threshold |
| Risk of extremist representation | Low (high effective threshold from constituency-level plurality) | Higher without a formal threshold |
| Government mandate clarity | High: manifesto of the governing party can usually be enacted | Lower: coalition agreements often dilute or trade away manifesto commitments |
No system performs well on every criterion simultaneously; this trade-off, rather than any single “correct” answer, is the central analytical point examiners are looking for.
Conclusion
The underlying tension between plurality/majoritarian and proportional systems is a trade-off between decisiveness and accountability on one hand and fairness and representativeness on the other.
FPTP delivers simple, usually stable, single-party government with a clear line of accountability, but at the cost of significant and sometimes extreme distortion between votes and seats, as starkly illustrated by the 2024 general election.
PR systems correct that distortion and better reflect a pluralistic, multi-party society, but generally produce coalition or minority government, dilute the direct constituency link (in some variants), and require voters to engage with more complex ballots and counting processes.
The UK’s own experience, using FPTP at Westminster while running AMS in Scotland and Wales and STV in Northern Ireland, provides a genuinely useful internal comparison, while the American case shows how majoritarian logic can produce even sharper distortions when layered onto federal structures such as the Electoral College.
There is no electoral system that is neutral among these values; the choice of system is, in effect, a choice about which values a political system prioritises.