How UK elections work: First past the post vs proportional representation explained

Labour is looking closely at reforming how UK citizens choose their MPs  (AFP via Getty Images)
Labour is looking closely at reforming how UK citizens choose their MPs (AFP via Getty Images)

For the first time, the London Mayoral election in May 2024 will be decided by a past the post voting system.

Considered a voting system that favours the major parties, Labour’s incumbent, Sadiq Khan is being challenged by Tory Susan Hall.

Others also vying for the role include Lib Dem’s Rob Blackie, Green candidate Zoë Garbett and Reform UK’s Howard Cox.

Having previously relied on the supplementary voting system, FPTP was introduced as part of the Electoral Reform Act 2022.

However, many campaigners have pointed out this will likely hand the role to majority party candidates while giving voters less choice.

Many politicians feel that recent changes to UK voting systems will make it harder for people to vote. Alongside FPTP, votes will also need to show a photographic ID when voting in upcoming elections.

“Let’s just call this what it is: a cynical attempt to make it harder for people to vote,” Khan said last year.

Meanwhile, mayor of Greater Manchester, Andy Burnham, has called for proportional representation to be used for general elections.

Burham previously said in June 2023: “I think we need to change the House of Commons as well, I think we need voting reform. I don’t believe all people in all places will be equally represented in Westminster until every vote matters.”

Currently, both the mayoral elections and general elections in the UK are decided using first past the post (FPTP), which electoral reform campaigners have long objected to.

But what do all these voting systems actually mean - and which is the best way to elect our representatives?

What is first-past-the-post and how does the voting system work?

FPTP is essentially what makes a slip of paper in a polling station mean something. For most elections in England and Wales, voters choose one candidate listed on a ballot paper. The candidate with the most votes wins and becomes MP. In this system, there is no such thing as second and third place choices on the ballot paper; the winner takes all.

FPTP can mean people end up voting for a party they don’t support to try to keep a particular candidate out
FPTP can mean people end up voting for a party they don’t support to try to keep a particular candidate out

Each party only fields one candidate, so voters sometimes have to weigh an individual they favour over a party they support.

Tactical voting is common under FPTP, where people vote for a particular candidate to help another party win to avoid being represented by someone they dislike.

How many seats are needed for a majority in the UK?

In Britain the House of Commons has 650 seats, and one party needs to win just over half – 326 – to secure a majority and be able to form a government. If no party manages to cross this line, a hung parliament results. Then the party with the most MPs may try to take power as a minority government, or parties may try to form a coalition among themselves or another general election could be called.

What is proportional representation?

Proportional representation is an electoral system in which the distribution of seats corresponds closely with the proportion of the total votes cast for each party. Therefore, if a party gained 40% of the total votes, a perfectly proportional system would allow them to gain 40% of the seats.

Why do some people want proportional representation? What are the advantages and disadvantages?

Tracy Brabin said that “power cannot be hoarded in government departments”. Proportional representation would mean voting is better reflected. “Under PR systems the number of seats in parliament reflects the number of votes cast overall in elections,” said the Independent.

It would also mean fewer “wasted votes”. In 2019, the Electoral Reform Society found that more than 22 million votes (70.8%) were “ignored because they went to non-elected candidates or were surplus to what the elected candidate needed” to win the seat.

However, some believe that proportional representation could mean that local issues suffer. Under this system, electoral constituencies would have to be bigger to have multiple seats to fill proportionately, which could mean that some issues get overlooked.

What other voting systems are there?

In using FPTP, Westminster is joined by the US Congress, Canada, India and many former British colonies in Africa and the Caribbean. But other countries use different systems.

Proportional voting

Most countries use proportional voting systems. These have a more direct impact on the result, so one third of votes for a single party would correspond to one third of seats in parliament.

Alternative vote

One different system – albeit not proportional – is Alternative Vote (AV), where ballot papers have second and third favourites. A candidate has to get 50 per cent of votes or more to win. If neither candidate has more than 50% of votes the top two compete in a second round runoff.

Tactical voting is less necessary under AV, as an unpopular candidate cannot win simply through the vote being split between several parties, as in FPTP.

AV is used to select the chairs of most Commons committees, and key votes in the House of Lords.

Supplementary vote

Mayors in England and Wales and police and crime commissioners previously elected via a supplementary vote.

Similar to AV, voters have a first and second choice on their ballot. If a first-choice candidate wins 50 per cent of votes, he or she wins outright. If not, candidates are whittled down to the two with the most votes, and then eliminated by whichever has least.

Tony Travers, professor of practice at the London School of Economics, explained: "First-past-the-post tends to favour the two biggest parties and parties which have concentrated votes in some constituencies, such as the Scottish National Party. It has generally created parties which are coalitions of different interests and also tended to squeeze out extremists.

"Many European countries use forms of proportional representation, where the number of seats received by each party is closely aligned to their vote share nationally. Australia and New Zealand have moved away from first-past-the-post towards more proportional systems."

How long has the current voting system been around?

FPTP can be traced as far back as the Middle Ages. In 1950 constituencies were redrawn to ensure every MP represented a roughly equal population, and FPTP was born in its modern form.

Critics of  FPTP say it leads to large amounts of wasted votes
Critics of FPTP say it leads to large amounts of wasted votes

Why do some people dislike it?

The main reason it is controversial is because some feel it fails to fully represent local areas.

Some say FPTP stokes division during election campaigns because parties channel their efforts into “swing seats”, where sitting MPs have small majorities, as opposed to “safe seats” – around two thirds of UK constituencies – where one individual or party can stay in power for decades.

Another key criticism levelled at FPTP is that small parties such as the Green Party are excluded and seen as a “wasted vote”. FPTP is also seen as responsible for tactical voting.

There can be discrepancies in the relationship between percentage of votes cast and won. In 2017 the Liberal Democrats won 12 seats on 7.4 per cent, while the SNP got 35 from 3% of votes.

However, its defenders say FPTP is easy to understand, avoids multi-party coalitions such as under Germany’s proportional system, and builds a strong bond between MPs and their constituents.

In 2011 Britain held a referendum on replacing FPTP with AV, but it was defeated by a two thirds majority.