The Liberal Democrats will directly court Labour voters in “blue wall” swing seats to try to build a critical mass of tactical voting in advance of the next election, Ed Davey has said before the party’s first in-person conference since 2019. The planned campaign of letters in Conservative-held commuter belt constituencies where the Lib Dems are the main challengers will be intended to persuade Labour supporters to lend their vote – not just as a means to change the government but because “they feel an affinity with us”, Davey said. Speaking to the Guardian ahead of the spring conference beginning on Friday, where he will make his first in-person leader’s speech to a party he has led for more than three years, Davey was at pains to not attack Labour, stressing that almost all seats the Lib Dems hope to win are Conservative held. The Lib Dems have ruled out any pre-election pacts, and Davey stressed that he and Keir Starmer, the Labour leader, have never discussed deals at all. While the Lib Dems’ trio of byelection successes in the past two years has been based on appealing to disaffected Conservative voters, it has also required supporters of other parties to join an informal anti-Tory voting block. The new direct approach to Labour voters is an attempt to focus minds before a general election expected next year, and to stress the liberal and internationalist credentials of a party some still associate with the 2010-15 Lib Dem-Tory coalition. The letters, from Davey himself, will set out the Lib Dems’ promise to immediately restore overseas aid to 0.7% of GDP, saying it was vital the UK properly supported people in places such as Syria and Afghanistan. “We want to make sure that in seats like these, people who would otherwise vote Labour aren’t voting for us just because we’re the only ones who can beat the Conservatives,” Davey said. “I’d like them to do it because they actually quite like us, and they feel an affinity with us. And I think they should with some of the positions we’ve been taking. “This isn’t being competitive against Labour in these seats, and I’m not trying to say you’re wrong to be Labour inclined. My push is to say: look at the Liberal Democrats. We share a lot in common.” The party’s gathering in York will be a chance for MPs and activists to hone tactics that have overturned significant Conservative majorities in Chesham and Amersham, North Shropshire, and Tiverton and Honiton. But inevitably it will also focus on indifferent national polling, with the party marooned for months on about 9% support. Davey, who saw last year’s autumn conference cancelled because it would have coincided with the Queen’s funeral, and followed a series of gatherings called off due to Covid, says he believes the party is doing far better than the polls suggest. “In actual elections, I think we’re doing extraordinarily well,” he said, pointing to gains in target areas at recent local elections. “I think the polls are quite a signal of anti-Conservative thinking. I’m not having a go at Labour, but I just don’t think that they have sealed the deal with people. “What that means is that where we are the clear anti-Conservative party, it is quite easy to persuade Labour voters to vote for us, because they’re really voting against the Conservatives.” A key test will come in May’s local elections, where Davey hopes his party will make gains despite these being seats last contested in May 2019, at the nadir of Theresa May’s popularity. Three prime ministers on, some Lib Dems worry their recent success in peeling away liberal-minded Conservative voters from a party led by Boris Johnson and Liz Truss could founder against the technocratic approach of Rishi Sunak. Davey professes to be unfazed, pointing to a recent Guardian story about the electricity grid near Sunak’s North Yorkshire home being upgraded to meet the power demands from his heated swimming pool. “He seems to me to be completely out of touch. I don’t think he is really winning people over,” Davey said. “And yes, he may appear to be a bit more together than Liz Truss or Boris Johnson, but it’s hardly a high bar.”