Election leaflets are providing “grotesque” information about how to vote tactically in the May elections, using national polling data, “dodgy” bar charts and doorstep surveys to support claims about parties’ chances of winning.Leaflets distributed by local politicians across England are claiming that only their party can win, or that another party “can’t win here”, when there is no good evidence to show this is true, a Full Fact investigation for the Guardian has revealed.Some of the campaigning material Full Fact looked at that contained a chart or graphic “failed to provide reliable evidence to back up a specific claim about how people are likely to vote locally, or were unsourced or misleading in some other way”, with examples from all the major parties.Readers who responded to a Guardian callout shared images of leaflets they had received.Some said they had at first thought a leaflet from the Conservatives was from the Green party, because it was printed in green with only a small Conservative logo.

Another expressed doubt about what they described as “very dubious” statistics from the Liberal Democrats showing a party was “the only sensible way to vote”,The polling and political analyst Peter Kellner, a former chair of YouGov, described some of the claims and data used in leaflets as “grotesque” and said spurious claims backed up by unreliable data were becoming increasingly common,“Because there are far more parties, and it is far less clear who you should vote for if you want to vote tactically, all parties are putting a lot of effort into convincing voters that they are the only option,” he said,“But if commercial companies were making some of these claims, they wouldn’t be allowed to get away with it,”Full Fact said good data on voting intentions was often not available in local elections and it was reasonable for political parties to address significant swings in the national polls.

But the organisation concluded: “Some of these leaflets could mislead people as they choose how to vote, for instance by claiming definitively that another party ‘can’t win here’ or that only one party can stop another.”Full Fact’s editor, Steve Nowottny, said: “There’s nothing wrong with parties making a case to voters, but too many leaflets are making overblown, dodgy claims with cherrypicked, misleading or unreliable data.”The organisation analysed 331 leaflets from across England uploaded to Democracy Club’s online archive in the first two weeks of April.Fifty-nine included a chart or graphic, with 14 of these unsourced or misleading or failing to provide reliable evidence about voting intention.Among the most egregious examples uncovered in the leaflet analysis was a Labour leaflet distributed in Ealing Common, a ward in west London, that warned voters not to “let Reform sneak in here” and included a bar chart that stated “Greens can’t win here”, with the addition of an arrow pointing to the green bar on the chart stating: “Wasted vote!” The Lib Dems, who control two of Ealing Common’s three seats, were the smallest bar.

The chart used the 2024 London assembly result for Ealing and Hillingdon, a much larger area.It added an extra bar that appears to reflect Reform national polling, “giving a picture that is misleading and confusing,” according to Full Fact.Kellner said: “What they’ve done is grotesque, and they’ve not been candid.The figures are in no sense indicative of Ealing Common.”Ealing Labour party said the diagram was “clearly an illustration of what could happen in a very competitive election, and can’t be taken literally, as no element of trying to predict the future can be”.

It conveyed “the very real and serious point that Reform are attempting to make real gains in Ealing”, and was “a common method of trying to make that point during an election campaign”, it said.A leaflet from the Green party in Gateshead showed Reform in the lead with the Greens in second, beneath a headline that said the “Greens are now the only alternative to Reform”.The chart stated it was based on opinion poll data from YouGov in March, but the same pollster currently puts the Greens third.Regardless, Kellner said a national poll was not a reliable indicator of local outcomes.A Reform leaflet from Chelmsford gave no source for its bar chart that put Farage’s party on 34% and the Conservatives and Labour on 16%.

Full Fact said while Reform had polled at 34% with at least one pollster in the past, it had not found an exact match for the Conservative and Labour figures at the same time.The bar chart was also “completely out of proportion”, it said.An online calibration tool suggests that if the Reform bar represented 34%, the height of the Labour and Conservative bars put them at about 9%, not 16%.“This is obviously misleading about the numbers themselves, whether or not they’re accurate or relevant,” Full Fact said.A Liberal Democrat leaflet from Eastgate and Moreton Hall in Suffolk stated “It’s Lib Dem or Reform here” while using a bar chart showing the Conservatives in second and the Lib Dems in third.

It used a YouGov quote stating the Lib Dems were “most likely to see off Reform UK”, probably a reference to a YouGov article from March 2025 that asked voters which party they would vote for if only Reform and the Lib Dems had a chance of winning.The Lib Dem candidate’s agent said: “The image is illustrative and not a true graph as such, which we emphasised by not putting in any indices.”Meanwhile, a leaflet from the Conservatives in Haslemere, a ward in west Surrey, told voters “Reform can’t win here”, apparently based on data for the whole of Surrey from the 2024 general election, which Full Fact said was “very unreliable evidence”.Full Fact said the assessment of leaflets was not intended to be fully representative of the national picture but instead looked at what voters might understand from the information given and whether it included reliable evidence.Kellner said that while “the mechanics of democracy work reasonably well” in the UK, disinformation peddled by political parties were a “small part of a larger jigsaw” that had led to trust in politics, politicians and institutions being more widely eroded in the past two decades.

“If one defines a healthy democracy as one where there is an open, free exchange of views and information which allows voters to make up their minds on the basis of truth rather than lies, then, yes, this is bad for democracy,” he said,