Labour is making dramatic progress in winning back pro-Brexit voters across the country as the coalition of support for the Tories built by Boris Johnson collapses, according to detailed analysis of Thursday’s local election results. Figures from the BBC’s “key wards” data, obtained by the Observer, show support for Keir Starmer’s party was up by seven points compared with 2021 in the most heavily pro-leave wards. The data also shows that while the Tories were down 2.5 points in the most pro-remain wards, their vote was down even more – by 5.5 points – in the most pro-leave wards. Senior Labour figures and leading academics said the data showed that the link between voting for Brexit and voting for the Tories is weakening – further encouraging Labour strategists to believe they can take back seats across the “red wall” and are on course to win the next general election. Robert Ford, professor of politics at Manchester University, who was part of the BBC’s results and analysis team, said that in the 2021 local elections there had been a very close correlation between those who voted Tory and those who had voted to leave the EU in red wall areas. “Voting leave was a very strong predictor of voting Tory. Now it is fading. Our statistical modelling shows it is much weaker now. We can say people are voting less in line with their Brexit preferences than they were a couple of years ago.” Stephen Fisher, professor of political sociology at Oxford University, who was also on the BBC results and analysis team, agreed that the connection between people voting Tory and those who voted leave had become looser, particularly since 2021. In Thursday’s poll Labour gained 536 seats, based on changes from the number of seats immediately after the previous elections, and took control of another 22 councils as it became the largest party in local government for the first time since 2002. In a terrible day for Rishi Sunak’s party, the Tories lost more than 1,000 seats – exceeding a figure that deputy prime minister Oliver Dowden had cited last weekend as, in effect, a worst-case scenario. The Liberal Democrats and Greens also made large gains. On Saturday night the Liberal Democrat leader Ed Davey said his party now had 20 Tory seats at Westminster in their sights at the next election, including those held by some of the biggest names in the party. They include those held by Michael Gove (Surrey Heath), Theresa May (Maidenhead) and Nadhim Zahawi (Stratford-on-Avon). Davey said: “As leader of the Liberal Democrats, my mission is to beat as many Conservative MPs as possible. In fact I believe it is our moral responsibility to do all we can to get these Conservatives out of power.” By making gains from the Tories in areas up and down the country – from Dover on the south coast to pro-Brexit voting Medway in Kent, East Staffordshire and Middlesbrough, Labour believes it is now forming the kind of coalition of support across different areas and types of voter necessary to end 13 years of Tory rule. Peter Kyle, the shadow Northern Ireland secretary, said Labour was on course to govern without the need for support from other parties. “We are going to win outright. We’re not going to need to go into coalition. Every indication is saying that is going to be the case.” Ford said the Boris Johnson coalition – which combined pro-Brexit former Labour voters with remainers in the south who backed the Tories because they disliked Jeremy Corbyn, was unravelling and that Labour was making important progress. “Keir Starmer wanted to rebuild his vote in leave voting areas … because he knows he can’t get a majority without doing that. Is that happening? Yes. Definitely. “What was the Conservatives’ goal? To try to hold together, somehow, the coalition that Johnson built in 2019, keeping the leave voters on board in the red wall and keeping the remain voters in the blue wall. Is that strategy working? Emphatically no. They are losing on both sides of that coalition.” Members of Starmer’s team believe important progress is being made in winning in working-class and previously staunch pro-Brexit areas. “Time and leadership (mostly the latter) have largely healed the twin poisons of Corbyn and Brexit,” said one shadow cabinet member. “There’s plenty of evidence for it from the elections. The interesting thing for me is the Tories don’t seem at all aware of the same dynamic hitting them. Johnson and Truss remain potent Tory forces, voters notice Rishi Sunak hasn’t fixed his party.” Starmer, a convinced remainer, led calls while Labour was in opposition for a second referendum on Brexit, but since winning the leadership he has refused to advocate even rejoining the single market or customs union, despite evidence mounting of the damage Brexit has done to the economy. Some pro-EU Labour figures have criticised him for failing to act on his convictions, but Labour strategists say he is being vindicated because Brexit voters are returning to the fold without the party leader having appeared to challenge the wisdom of their 2016 vote. While the disastrous results for the Tories have led to behind-the-scenes sniping from some supporters of Johnson against Sunak, there is no serious attempt to plot a challenge to him as leader and prime minister. Some Tory MPs who won seats for the first time under Johnson are worried, however, that the party appears to have abandoned the former prime minister’s “levelling up” agenda. One said Labour’s message that “nothing in Britain works” was landing with voters. “There are some very frustrated and disappointed Conservatives who don’t feel like levelling up is really happening,” said one. “They think it’s all talk, no action. Levelling up has clearly been abandoned. We’ve lost control of that narrative and Labour has made it seem like a pipe-dream fairy tale that died with Boris Johnson. Beyond the end of this year, people have to see he delivered on his five pledges and actually understand what Conservatism is under Rishi Sunak.” Other Tory MPs said they had been alarmed by the number of Labour activists in their areas, stating that they felt “abandoned by CCHQ”. A senior MP in an area targeted by the Lib Dems said that Sunak’s decision to take a hard line on immigration had confirmed a “lurch to the right” that was holding back a recovery. “A certain type of Conservative voter now is put off by some of the lurch-to-the-right stuff on certain issues, principally the nonsense around immigration policy.” • This article was amended on 9 May 2023 to provide information about the basis on which the number of seats gained by Labour was calculated.