Advantages and disadvantages of PR / Proportional Representation electoral system

17 Oct 2025

by PIN Communications

Proportional Representation: The advantages and disadvantages of this electoral system

Proportional representation (PR) is a family of voting systems designed where the distribution of seats corresponds closely with the proportion of the total votes cast for each party or individual candidate. Instead of one group sweeping most of the representation with only a portion of the vote, PR aims to reflect voters’ preferences more fairly across the results.

PR systems are used as alternatives to First Past the Post and other winner-takes-all methods, which often favour larger parties and can leave smaller groups without a voice. With PR, smaller parties have a better chance of gaining seats, giving voters a wider range of views represented in elected bodies.

Different forms of Proportional Representation

There are many different forms of proportional representation. Some are focused solely on achieving the proportional representation of different political parties (such as list PR) while others permit the voter to choose between individual candidates (such as STV-PR). The degree of proportionality also varies; it is determined by factors such as the precise formula used to allocate seats, the number of seats in each constituency or in the elected body as a whole, and the level of any minimum threshold for election. Common PR systems include Single Transferable Vote (STV), Additional Member System (AMS), and list proportional representation, each with different ways of translating votes into seats.

These approaches are used as alternatives to First Past the Post and other winner-takes-all approaches, which often benefit larger parties and can leave smaller groups under-represented. With PR, smaller parties have a more realistic chance of winning seats, helping to create elected bodies that include a broader range of political views.

What are the advantages of a PR electoral system?

Moving to proportional representation (PR) in the UK may offer minority parties and independent candidates a better chance of winning seats in Parliament.
The current First Past the Post electoral system is considered unrepresentative, as candidates can be elected with a very small share of the votes while all other votes cast in the constituency are wasted.
In the 2024 UK general election, Terry Jermy was elected MP for South West Norfolk with just 26.7% of the vote… one of the lowest winning vote shares in that election. This means nearly three‑quarters of voters in the constituency cast their ballots for other candidates, but those votes had no impact on who became the MP.
In fact, several MPs won their seats with well under 30% of the vote. Therefore, a large majority of voters in those constituencies preferred other candidates but weren’t represented by their choice. In East Londonderry and North Antrim, winners also took their seats with less than 29% of the vote.

PR ensures that the parties would have to appeal to their core supporters, rather than a small number of ‘swing voters’ in marginal seats. It could be argued that PR delivers fairer treatment of minority parties and independent candidates.
Under PR you could say that fewer votes are ‘wasted’ as more people’s preferences are taken into account, therefore offering greater and perhaps more-representative choice for voters.
In a City of Edinburgh Council by-election last June, voters ranked candidates under Single Transferable Vote (STV) – a proportional system also used in Scottish local elections. These were the first-reference shares:
Labour – 20.8%
Liberal Democrats – 20.4%
Green – 18.2%
SNP – 14.5%
Conservative – 13.8%
Reform UK – 7.9%

PR rarely produces an absolute majority for one party, however, it could be argued that PR ensures greater continuity of government and requires greater consensus in policy-making.

In the example above, no single candidate had close to a majority of first‑choice votes. Under First Past the Post, Labour would have won with only 20.8%, meaning nearly 80% of voters didn’t help elect the winner.

Disadvantages of using a PR system

Under First Past the Post, MPs serve the constituency they campaign in. This makes them more inclined to tackle important local issues. As MP for Richmond, Rishi Sunak has repeatedly focused on local transport and infrastructure concerns including campaigning for improvements to local rail services including better road links. As he represents one specific constituency under First Past the Post, he regularly takes up community issues with national government departments.
PR can potentially provide a route for extremists to force their way into the political mainstream: under a FPTP electoral system this would be unlikely to happen.
Under Sweden’s proportional representation system, the Sweden Democrats – a party with anti‑immigration roots – grew from no seats into one of the largest parties in the Swedish Riksdag after crossing the electoral threshold. In the 2022 Swedish general election, the Sweden Democrats won around 20.5 % of the vote and became the second‑largest party, and have since supported governing coalitions, giving them direct influence in national politics.
Some would say that PR produces ‘weak’ coalition governments rather than ‘strong’ majority governments, which arguably can lead to indecision, compromise and even legislative paralysis.

PR can also reduce accountability to voters, as an ousted party of government can retain office by finding new coalition partners after an election.
Under Ireland’s proportional representation with Single Transferable Vote (STV) system, neither major party won a majority in the 2024 general election. Instead, Fianna Fáil and Fine Gael, which had both been governing together in coalition before the election, ended up negotiating again after the vote to form a new coalition government. Micheál Martin became prime minister last January 2025, backed by a coalition of Gael and several independents, and will rule for the first three years of the five-year government, with Simon Harris of Gael taking over in November 2027. This meant that the incumbent camp effectively retained power rather than being replaced by a single opposition party with more support.
Another disadvantage is that PR list systems could possibly weaken the link between the elected representative and their constituency. The greater complexity and choice that PR allows can put voters off voting, by requiring them to have a greater knowledge of individual and party positions.

FAQs

Where is proportional representation used in the UK?

In the UK, Proportional Representation is not used for general elections, which still use First Past the Post. Scotland uses AMS for its Parliament and STV for local council elections, allowing voters to rank candidates and balance representation. Wales uses AMS for the Senedd, while Northern Ireland Assembly elections use STV. The London Assembly combines FPTP constituency seats with proportional list seats. These systems help smaller parties and voter preferences gain fairer representation compared with FPTP.

Does PR make governments more likely to form coalitions?

Yes! While this can encourage compromise, it can also slow decision-making and reduce clear mandates.

Would PR benefit small parties in the UK?

It would! PR allocates seats roughly in proportion to the total votes a party receives, rather than requiring them to win individual constituencies outright. This means smaller parties might win more seats and gain representation that reflects their actual support. Under First Past the Post a party with significant national support can win few or no seats if its votes are thin across constituencies. It could be argued that PR would make elections fairer and give voters a wider choice.

Why hasn’t the UK adopted PR for parliament?

The UK uses First Past the Post mainly due to tradition and simplicity. It produces clear winners and strong local representation, and larger parties that benefit from FPTP have resisted change. Past reform attempts, like the 2011 Alternative Vote referendum, failed, showing limited public support for PR.

How could an organisation’s electoral needs be guided?

For an independent assessment of your organisation’s electoral needs and impartial advice and guidance about the electoral system that best fits your requirements speak to PIN Communications.

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