Small changes in turnout could substantially alter election results in the future because the UK now has a multiparty system with majoritarian voting rules, a new study warns.
Last year's General Election, which saw a marked increase in the number of candidates and a fragmented vote, will have an impact on the mandate of the Labour government, an expert has said.
The research shows how the 2024 election tested the boundaries of the first-past-the-post system and the result means the UK has an uncertain electorate with diverse preferences. While the result led to a stable government there is plenty of instability.
The study, by Dr Hannah Bunting, from the University of Exeter's Elections Centre, shows how Labour was able to secure a third-largest victory in terms of seats, on the lowest vote share of a winning party in modern times. On an increase of just 1.7 percentage points in national vote share, they won 211 seats more than suggested by the 2019 notional results. In 2024 there were few areas where the electorate clearly preferred a single party over all others.
Dr Bunting said: "While the 2024 General Election results might have produced a stable government, under the surface and throughout the British population there is plenty of instability. Last year the public knew who they did not want, but the vote shares showed they did not uniformly agree on who they wanted to govern them.
"Labour overwhelmingly won the most seats, but they did so on small margins. The rise of Reform UK, the Greens, independents and others across the country was the driving factor for the party to win the election on such a small percentage of the overall vote.
"The Liberal Democrats won eight times as many seats as the previous election and returned their highest number of MPs since 1923 on a vote share increase of less than a percentage point and a 2.1% lower vote share than Reform UK. The party achieved their best election result by improving in only three regions."
Dr Bunting measured how competitive constituencies were by assessing the number of parties that had a substantive impact on the results, and how evenly spread the votes were across multiple candidates. This shows in 2019, there were seventeen three-way marginals; in 2024 there are more than 100.
More than 75 per cent of constituencies had at least three effective parties. The average was 3.4 per cent in 2024, and 2.4 across all other years.
Dr Bunting said: "This tells us the party system fragmented and suggests that the electorate have diverse ideas about the representatives they want to see in parliament.
"Some seats were won by just a handful of votes, signifying fierce competition in the constituency. There were twelve where the winner was victorious on a margin of less than 200 votes and eighteen on less than a percentage point, 112 were won with a majority less than 5%, almost twice the number with the same margin in 2019."
The highest constituency share of the vote for the Conservatives was 53.3 per cent, in all others they received less than half of votes. In 2019 they won at least half the votes in 288 constituencies and their highest share was 76.5 per cent. In 2024, the Greens placed higher than the Conservatives in seventy-eight seats. Reform UK placed higher than them in 140 seats.
The study says some of this reduced vote share is a function of fragmentation as Labour's landslide was won with just seventy constituencies where they took at least 50 per cent of the votes, down from 122 in 2019, which was their worst performance in eighty-four years. The Liberal Democrats more than tripled the number of seats where they won a majority of votes, from five in 2019 to eighteen in 2024.
Across Britain, turnout dropped by 7.8 percentage points to 59.8 per cent. This was the second-lowest post-war turnout, and only slightly above the record low in 2001. The study says this may be due to the greater number of parties and increase in the number of citizens that are unsure of who to vote for.
