Britons are more politically promiscuous than ever

The 100-year-old duopoly of Conservatives and Labour in British politics is dying. At the general election in 2024 the two parties attracted 57% of ballots cast, their lowest tally since the 1910s, when Labour was in its infancy. Today, judging by the polls, they amass just 38% of prospective voters between them (split more or less equally). Yet no party is racing away with the spoils: the Liberal Democrats are at 12%, the Greens at 17% and Reform UK 25%. Voters are keeping their options open.

Using data from More In Common, a polling firm, The Economist has built a model which calculates the probability of a voter supporting a party based on eight demographic characteristics—sex, age, ethnicity, region, education, employment status, type of housing and whether it is in a rural or urban area. We created 275,000 permutations of every characteristic to represent each of Britain’s 55m adults. We find that over the past two years more voters have swung away from the party they last voted for than ever before.

That is in part due to Labour’s support ebbing away rapidly after the general election in 2024. Take the party’s least-sticky voters: young black female students in the South East. In 2024 Labour attracted about four in five of their votes. Today, fewer than one in five say they would back it (the party’s policies on Gaza helped drive many to the Greens). Only 2% of adults are now more likely to vote Labour than they were in 2024 (middle-aged Asian women in the West Midlands are one such group).

Labour’s weakness has primarily benefited the populist-left Greens and populist-right Reform. More than nine in ten Britons are now more likely to consider voting for either of those two parties than they were in 2024. But whereas the typical Reform voter is little changed—a poorly educated, old white man who lives in a town in the south of England—the typical Green voter has become younger and more urban. The Greens are now the most popular party for anyone under the age of 28, up from third in 2024.

The effects of political promiscuity are also plain in changes in the predictive power of voters’ characteristics. In 2024 someone who identified as being black had, other things being equal, a 25 percentage-point greater chance of voting Labour compared with other voters. Today that impact is 16 percentage points. The effect of old age—the most important predictor of a Tory supporter—has shrunk from 17 percentage points to ten.

Party loyalty is truly a thing of the past. In 2024 some 40% of Britons who had voted in 2019 switched parties, the highest share since the 1930s. If a general election were held tomorrow, by our calculations nearly 50% of voters would switch parties. In 2024 around 2.5m people had a greater than 60% chance of voting for one particular party. Now just 600,000 are that solid. About one-fifth of Britons have a profile for which four or more parties have a 15% chance of gaining an individual’s vote. That will make election campaigns, which rely on targeting likely supporters, trickier.

Britain’s electoral system was not built for this behaviour. Politics driven by impatient voters—who lurch to the hottest new thing from one election to the next—will leave most people disappointed. Dissatisfaction tends to increase distrust. The local elections on May 7th, when the Labour Party is expected to lose thousands of council seats, will be the first proper test of this new swingtime era.■