Labour and the Conservatives won a combined 57.4% of the vote at the 2024 election — the lowest share since the franchise was widened to near-universal suffrage. National polling since the election puts the two parties even lower, with Reform UK now level with Labour.
For most of the postwar period, Labour and the Conservatives between them took the overwhelming majority of the UK vote. In 1951, the two parties won a combined 96.8% — between them they were, for most voters, the only realistic choice.1 That dominance eroded in fits and starts: a Liberal revival in the 1970s pulled the combined share down to around 75%, and a further slide through the 1980s and 2000s took it below 65% by 2010.1
The 2015–2019 period looked, briefly, like a reversal. Brexit polarised the electorate around the two largest parties, and by 2019 their combined share had recovered to 75.7%.1 The 2024 election broke that pattern decisively: Labour's 33.7% and the Conservatives' 23.7% added up to just 57.4%, below every UK general election on record back to 1918.12
Part of what makes 2024 notable is that fragmentation had looked, for a decade, like a two-step process: it rose sharply in 2015 as UKIP, the Greens and the SNP all gained ground, then partly reversed as Brexit squeezed votes back toward the two largest parties in 2017 and 2019.1 2024 did not follow that script. Reform UK's vote share (14.3%) was more than four times its 2019 predecessor's, the Green vote (6.7%) was the party's best ever, and the Liberal Democrats took their largest number of seats since 1923 — even though their vote share barely moved.2 For the first time in the era of universal suffrage, four parties — Labour, the Conservatives, Reform UK and the Liberal Democrats — each won more than 10% of the UK vote at the same election.2
An MRP poll for PLMR by Electoral Calculus and Find Out Now — fieldwork 23–30 June 2026, sample 5,545 GB adults recruited from an online panel — put Labour and Reform UK level on 22%, with the Conservatives on 20%: a combined Labour + Conservative share of 42%, some 15 points below the 2024 result.3 That is not an isolated reading. Separate voting-intention polls by YouGov (5–6 July) and Opinium (1 July) put the combined two-party share at 41% and 39% respectively, with Reform UK leading in both.45 All three are single snapshots with a margin of error of around 2–3 points on each party's figure, so the precise numbers should be read as a range rather than exact values — but the range itself, 39–43%, sits well clear of the 2024 result.
Topline figures show the size of the shift but not its mechanism. To get at that, YouGov asked a sample of nearly 20,000 GB adults how they would vote now, broken down by how they voted in 2024. Only 41% of 2024 Labour voters still back Labour; only 50% of 2024 Conservative voters still back the Conservatives.8 Weighting each party's retention rate by the share of the vote it actually won in 2024 gives a blunt measure of what survives: just 25.7% of the 2024 UK vote is now a retained Labour or Conservative vote — under half the 57.4% the two parties won between them.
The direction of the leaks matters as much as their size. The largest single defection is Conservative to Reform UK: 26% of the party's 2024 voters, worth 6.2 points of the 2024 UK vote. The second largest runs the other way — Labour to the Greens, 17% of Labour's 2024 voters and 5.7 points.8 The two governing parties of the postwar era are not losing ground to one insurgent but to two, on opposite flanks, which is part of why no single national swing figure describes the period well. The largest destination of all, though, is not a party: a fifth of the 2024 vote now sits with people who are undecided, say they would not vote, or have moved somewhere the survey did not separately report.
A shrinking two-party vote share matters more under Britain's electoral system than it would under a proportional one, because first-past-the-post rewards concentrated support and punishes evenly-spread support almost regardless of a party's overall vote total. Labour's 33.7% of the vote in 2024 converted into 63.2% of seats — a landslide majority built on the lowest vote share of any single-party majority government on record.2 At the other extreme, Reform UK's 14.3% of the vote, spread thinly across the country, returned only 0.8% of seats.2
The next general election is not due until 2029, so three years of polling volatility could still separate the current numbers from a real result — MRP models translate a snapshot of opinion into notional seats, they do not forecast the future. The most detailed poll used here was fielded in the week after Keir Starmer announced his resignation but before Andy Burnham was confirmed as Labour leader on 17 July and became Prime Minister on 20 July, so it may not fully reflect any "Burnham effect" on Labour's standing.36 It is also unclear how much of Reform UK's current support would survive contact with an actual ballot: opposition parties historically poll better mid-term than they perform at a general election, once local candidates, campaigns and tactical voting are in play. The voter-flow exhibit also rests on respondents' recall of how they voted two years ago, which surveys consistently find is imperfect and tends to drift toward the winning party; and roughly a fifth of the 2024 vote in that exhibit sits in a residual band whose destinations were not separately published, so it cannot be attributed to any party.
Political scientists broadly agree on the numbers; they disagree on what they mean for the next election.
Academic analysis of the 2024 result describes it as the most fragmented UK election on record by several measures at once — the highest "effective number of parties" and the lowest two-party vote share since Labour became a major force — arguing this continues a longer-run drift away from two-party politics that the 2017–2019 Brexit elections only interrupted.7
Pollsters' own tactical-voting research suggests some of Reform UK's current strength is soft: modelling for the July 2026 MRP found that anti-Reform tactical voting alone could cost the party dozens of seats, implying the FPTP squeeze that pulled votes back to the two largest parties in 2017 and 2019 could reassert itself as a real election nears.3
Held out of this piece to keep it focused on the UK-wide two-party trend: