Slight changes to turnout or support could make the difference between momentous losses and colossal gains for political parties in next week's local elections, new results projections show.
The new analysis shows this year's voting will see many close contests - decided by just a few percentage points – and there is potential for Labour to suffer record-breaking losses.
The projections suggest there could be a difference of less than five percentage points between the vote share of Labour and the Greens.
Labour looks set to lose at least half of incumbent council seats being defended. However the sizable majorities of Labour councillors who won seats four years ago, and the fact their challenge comes from a fragmented group of other parties, could protect some candidates.
The analysis, by Dr Hannah Bunting, co-director of the University of Exeter Elections Centre, suggests Reform are set to get the highest national equivalent vote share, while the Conservatives could come fifth in terms of total number of seats won. The Liberal Democrats could replace the Tories as the second largest party of local government. The Greens may win five times the number of seats they start with.
Dr Bunting said: "Voters are faced with extensive choice and are not as yet coordinating around a single party. Slight changes in turnout or party support could produce wildly different outcomes."
The analysis says:
- If Labour's support is down 15 percentage points this would result in around 500 seat losses where councillors have a majority of 15% or less.
- The more realistic scenario is a 20-point swing away from Labour, which when applied uniformly means the party loses every seat they hold with less than a 40% majority. That would create an outcome of 1,750 losses, meaning the party would hold on to only a third of the seats they defend.
The analysis also says:
- If the Conservative Party's support is down ten percentage points this would mean the loss of 350 seats where their majority is less than 10%.
- More likely is a ten-point swing, meaning total losses would be 700-800 seats.
Dr Bunting used real votes in recent local by-elections to estimate national equivalent vote share. The latest estimates, for April 2026, show Reform UK sit at just over a quarter, nearly seven points clear of Labour who remain in second place. The Greens have been on a steady ascension over the past six months to reach 14.3%, whereas Reform are only slightly higher than their typical performance in the same period. The Conservatives enjoyed a modest increase in February but have otherwise been on a consistent decline since shortly after the general election - they are at 18.3%, just one point below Labour, and 1.7 points above the Liberal Democrats.
Dr Bunting also looked at the majorities the parties defend in these council seats and calculated their potential losses based on swings against them.
She took the baseline election results for each seat in its corresponding previous election year and combined them with demographic data, to compute a full seat-level projection.
- Reform to win the most seats, finishing with 27% of all seats contested.
- Labour would lose the most seats and are forecast to retain 44% of those they defend.
- The Liberal Democrats would come a close third for final seat totals.
- The Conservatives trailing at fifth and losing two thirds of their incumbents.
- The Green Party are estimated to pick up the second most gains, finishing with almost five times the number of seats they began with.
- Labour would lose almost an equal number of seats to the Greens as they do to Reform UK.
