Full Breakdown
Reform UK's Decline and Labour’s Lead in the Latest UK Seat-by-Seat Poll
By Drooid · · How we work
Core Event
A new YouGov multilevel regression-post-stratification (MRP) model, based on nearly 17,000 respondents surveyed between August 23 and September 18, projects that if a general election were held today Labour would win 241 seats, the Conservatives 130, and Reform UK 123. The model also forecasts the Liberal Democrats on 71 seats, the SNP on 48, Plaid Cymru on 15, and the Greens on 9. This reverses a YouGov projection a year earlier that placed Reform on 311 seats and the Conservatives on 45. 37 % of constituencies are decided by margins of five points or less, making the outcome sensitive to tactical voting.
Background & Context
Reform UK briefly out-polled both Labour and the Conservatives in 2024, coinciding with Andy Burnham’s ascent to prime minister in July 2025. Subsequent polling by Survation and 38 Degrees, covering more than 8,000 voters, introduced a tactical-voting scenario that could push Reform from second place to fourth, cutting its seat total by roughly 90 seats even as its vote share rises.
Data & Statistics
- YouGov seat projections (Aug 23-Sep 18): Labour 241, Conservatives 130, Reform 123, Lib Dem 71, SNP 48, Plaid Cymru 15, Greens 9.
- National vote-share snapshot (Sept 20-21 poll): Labour 23 %, Conservatives 21 %, Reform 21 %, Greens 14 %, Liberal Democrats 12 %.
- Tactical-voting willingness (Survation/38 Degrees): 40 % would back a party that cannot finish in the top two locally; ? 18 % say they would switch to the stronger local contender.
- Projected impact of full tactical voting: Reform could fall to 62 seats, Labour rise to 319 seats (six short of a majority), and the Conservatives gain 46 of the 91 seats where Reform would otherwise lead.
- Regional variations: In Wales, YouGov projects Labour retaining only two of its 27 2024 seats, with Plaid Cymru on 15 and Reform on 14.
Why It Matters / Impact
The projected composition produces a hung parliament: Labour would be 85 seats short of a majority, and even a combined Conservative-Reform bloc would total 253 seats, well below the threshold. Consequently, any governing arrangement would require coalition-building with the Liberal Democrats, the Greens, the SNP or Plaid Cymru. The narrow margins amplify the strategic importance of tactical voting; a coordinated shift toward Labour or the Conservatives could overturn Reform’s leads and reduce its leverage in right-hand negotiations.
Official Statements & Responses
- (The Independent)
Conflicting Reports & Gaps
- The Survation tactical-voting model suggests Reform could drop to 62 seats under full coordination, whereas the YouGov MRP places Reform at 123 seats without assuming coordinated voting.
- Vote-share figures differ: The Guardian’s tactical-voting poll reports Labour at 42 % of seats with 28 % of the vote, while YouGov’s September 20-21 poll records Labour at 23 % nationally, the Conservatives and Reform each at 21 %.
- Both models acknowledge high uncertainty in marginal constituencies, but neither predicts the exact timing of any future election, which remains scheduled no earlier than 2029.
Verbatim Quotes
- “Labour head into their conference with a lead in our polling for the ninth week in a row, although that lead remains narrow,” — Luke Tryl