3.1.2.2a - UK Electoral Systems
Scope: This lesson explains how majoritarian and proportional electoral systems convert votes into representatives in UK parliamentary and devolved-body elections. It focuses on FPTP, AMS, STV and the limited relevance of SV/AV-style systems, then evaluates proportionality, representation, strong government and wasted votes.
The Core Trade-Off
An electoral system is the set of rules that converts votes into representatives or office-holders. In a representative democracy, citizens do not usually make policy directly; they use elections to choose people who will govern, legislate, scrutinise and represent them.
Two terms need careful handling:
| Term | Meaning | Why it matters |
|---|---|---|
| Majoritarian system | A system that tends to produce a clear winner, usually through single-member contests. | It can make government formation easier, but may distort the relationship between votes and seats. |
| Proportional system | A system designed so parties' seats broadly reflect their share of votes. | It can improve representativeness, but may make coalition or minority government more likely. |
| Plurality | Winning with more votes than any other candidate, even if below 50%. | FPTP is technically a plurality system, though AQA usually groups it with majoritarian systems. |
| Wasted votes | Votes that do not help elect a representative, or votes beyond what a winning candidate needed. | High levels of wasted votes weaken the claim that each vote has equal influence. |
Suffrage is the legal right to vote. Participation is the act of using that right. Electoral systems do not decide who has the vote, but they do decide how effectively participation is translated into representation.
The big AQA judgement is not "which system is best?" in the abstract. It is: which democratic value are you prioritising?
| Criterion | Question to ask |
|---|---|
| Proportionality | Do seats broadly match votes? |
| Representation | Do voters get clear local representatives and a legislature that reflects political diversity? |
| Strong government | Does the system help produce a government able to pass its programme? |
| Voter choice | Can voters choose between candidates, parties or ranked preferences? |
| Accountability | Can voters clearly remove a representative or government? |
| Simplicity | Is the system easy to understand, vote in and count? |
FPTP And Westminster
First Past the Post is used for elections to the House of Commons. The UK is divided into 650 constituencies, each electing one MP. Each voter has one vote. The candidate with the most votes wins; they do not need an absolute majority.
This creates a direct constituency link. Every area has one named MP, and voters know who to reward or punish at the next election. It is also simple: one cross, one local winner.
FPTP's central weakness is disproportionality. Because the national result is just the sum of 650 local contests, a party can win many seats by being narrowly ahead in the right places, while another party can gain many votes spread thinly across the country but win few seats.
The 2024 general election is the sharp current example:
| Party | Vote share | Seat share | Seats |
|---|---|---|---|
| Labour | 33.7% | 63.2% | 411 |
| Conservative | 23.7% | 18.6% | 121 |
| Liberal Democrat | 12.2% | 11.1% | 72 |
| Reform UK | 14.3% | 0.8% | 5 |
| Green parties | 6.7% | 0.6% | 4 |
That evidence supports both sides of the debate.
| Advantage | Evaluation |
|---|---|
| It can create strong single-party government. | Labour's 2024 majority gave the government a clear Commons majority, but it rested on just over a third of the vote. |
| It gives voters a local MP. | The local link is clear, but many voters live in safe seats where the result is predictable. |
| It can remove governments decisively. | Voters removed the Conservatives after 14 years in office in 2024, but the scale of the seat change was amplified by the system. |
| It is simple to use and count. | Simplicity does not guarantee fairness in vote-seat conversion. |
The case against FPTP is strongest when discussing wasted votes. Votes for losing candidates do not help elect anyone. Votes piled up for a winning candidate in a safe seat may be surplus to what was needed. This can encourage tactical voting, where voters choose the candidate most likely to defeat a disliked opponent rather than the candidate they most prefer.
AMS And Devolved Representation
The Additional Member System is a mixed system. It combines a local constituency vote with a regional list vote. It is used for Scottish Parliament elections and London Assembly elections. For AQA, the Scottish Parliament is the clearest devolved-body example.
Scottish Parliament elections use 129 MSPs: 73 constituency MSPs and 56 regional MSPs. Each voter has two votes:
- Constituency vote: choose one local candidate. The winner is elected by FPTP.
- Regional vote: choose a party or independent candidate list in a larger region.
- List allocation: regional seats are distributed using a formula that takes account of constituency seats already won, so parties under-represented in the constituency contests can gain list seats.
This is why AMS is more proportional than FPTP but less purely proportional than a full national party-list system. It keeps the local link while adding a correction mechanism.
The 2026 Scottish Parliament result shows the effect. The SNP remained the largest party with 58 seats, while Labour and Reform UK each won 17, the Greens 15, Conservatives 12 and Liberal Democrats 10. Six parties were represented, and no party had the 65 seats needed for an overall majority.
| AMS advantage | AMS disadvantage |
|---|---|
| It reduces wasted votes because the list vote can still affect representation even if a voter's constituency candidate loses. | It is more complex than FPTP, especially because the regional allocation depends on constituency results. |
| It represents smaller parties better than FPTP. | Constituency and regional MSPs can create two types of representative, which may confuse accountability. |
| It preserves local constituency representation. | If one party dominates constituencies, the number of list seats may not fully correct disproportionality. |
| It often produces a legislature that reflects political diversity. | It can make single-party majority government less likely, increasing the chance of minority or coalition government. |
The AQA judgement is balanced: AMS improves representativeness and reduces wasted votes, but it may weaken the "strong government" argument that supporters of FPTP value.
STV And Preferential PR
The Single Transferable Vote is both preferential and proportional. It is used for Northern Ireland Assembly elections and local elections in Scotland and Northern Ireland.
Under STV, constituencies are multi-member. Voters rank candidates: 1, 2, 3 and so on. A candidate is elected when they reach a quota. If a candidate has more votes than needed, surplus votes can transfer to next preferences. If no one reaches the quota, the lowest candidate is eliminated and their votes transfer. The process continues until all seats are filled.
STV changes the meaning of voter choice. A voter can rank candidates from different parties, or choose between candidates from the same party. That makes representation more candidate-centred than a closed party list.
| STV strength | Why it matters |
|---|---|
| High proportionality in multi-member seats | Parties and viewpoints can be represented in closer proportion to support in the area. |
| Fewer wasted votes | Transfers mean votes for losing or already-elected candidates can still help elect another preferred candidate. |
| More voter choice | Voters can rank individuals rather than just choose a party label. |
| Useful in plural societies | Northern Ireland's Assembly benefits from a system that can represent multiple parties and communities. |
| STV weakness | Why it matters |
|---|---|
| Complex counting | Quotas and transfers are harder to explain than FPTP. |
| Larger constituencies | The single local representative link is weaker because each area elects several representatives. |
| Less likely to produce single-party dominance | This may improve representation but can make government formation more negotiated. |
| Intra-party competition | Candidates from the same party may compete against each other for lower preferences. |
STV is a strong answer to wasted votes, but not a simple answer to strong government. That trade-off is exactly what AQA expects students to analyse.
SV And AV-Style Systems
Supplementary Vote and Alternative Vote are important to understand as preferential single-winner systems, but they should not take over this lesson. They are not proportional systems, and they are not the current system for House of Commons elections.
| System | How it works | AQA relevance |
|---|---|---|
| Supplementary Vote | Voters mark a first choice and may mark a second choice. If no candidate wins over 50% of first preferences, all but the top two are eliminated and relevant second preferences are added. | As of 2026, Commons Library records it for mayoral elections in England and Police and Crime Commissioner elections. It is useful as a contrast with FPTP. |
| Alternative Vote | Voters rank candidates. The lowest candidate is eliminated and votes transfer until one candidate has over 50%. | The UK rejected AV for Commons elections in the 2011 referendum, with 67.9% voting against change on 42.0% turnout. |
These systems can strengthen the personal mandate of a single winner because the final winner may need broader preference support than under FPTP. They can reduce the problem of a candidate winning on a small plurality in a crowded field.
But SV and AV do not solve national disproportionality. If each constituency still elects one winner, parties with geographically concentrated support remain advantaged and parties with evenly spread support may still struggle to win seats. AV can even exaggerate a landslide if lower preferences flow towards an already competitive major party.
So the clean distinction is:
| Family | Main goal | Main limitation |
|---|---|---|
| FPTP | Clear local winners and potentially strong government | High wasted votes and disproportionality |
| SV/AV | Broader single-winner mandate through preferences | Still not proportional |
| AMS | Mix local representation with party proportionality | More complex and only partly proportional |
| STV | Proportional representation with voter-ranked candidates | Complex count and weaker single-member local link |
AQA Evaluation
A rigorous AQA answer should avoid one-sided labels such as "FPTP is unfair" or "PR is democratic". Instead, connect each system to a democratic value and then test it with evidence.
For FPTP, the strongest argument is government effectiveness. The 2024 election produced a clear Labour majority, making it easier for the government to pass legislation. The counter-argument is legitimacy and proportionality: Labour's seat majority was much larger than its vote share, while Reform UK and the Greens had far more votes than seats.
For AMS, the strongest argument is balanced representation. The Scottish Parliament keeps constituency MSPs but uses regional list seats to correct some disproportionality. The counter-argument is that it is more complex and often produces minority or coalition politics, so voters may find it less clear who is responsible for government decisions.
For STV, the strongest argument is voter choice and low wasted votes. Preferences and transfers mean more voters can influence the final result. The counter-argument is that multi-member constituencies and quota counts are harder to understand, and the local link is less direct than one MP for one constituency.
For SV and AV-style systems, the strongest argument is that preferential voting can improve the mandate of one office-holder. The counter-argument is that these are still single-winner systems and should not be mistaken for proportional representation.
A useful judgement sentence is:
"The best electoral system depends on whether democratic legitimacy is judged mainly by strong and accountable government, or by the proportional representation of voters' preferences."
That sentence can anchor both 9-mark explain/analyse answers and 25-mark essays. The evidence then decides the strength of the judgement: 2024 supports criticisms of FPTP disproportionality, while Scotland's AMS example supports the claim that proportional systems represent more parties but make government formation less majoritarian.