The turnaround was swift in Mid Bedfordshire. Less than 24 hours after Nadine Dorries said she was standing down as its MP, the traditional Tory blue seat was engulfed in a yellow glow. Glorious rays of sunshine cloaked the leafy constituency on Saturday morning as at least 130 Liberal Democrat activists descended on the area before a crucial byelection that will test Rishi Sunak’s grip on power. Two days later, the Lib Dem campaigners were still there but the weather had turned and the constituency, which Dorries held with a 24,000 majority in 2019, was now at risk of flooding. Sir Ed Davey, the Lib Dem leader, on Monday made his second trip to Mid Bedfordshire, this time squeezed into what he called his “sewage wellies”. But minutes after dipping his hands into the River Lea as he warned about water pollution, he was forced to run out of the Barton Hills nature reserve as heavy downpours struck. The Lib Dem parade had quite literally been rained on, forcing its leader to take cover in his car beside St Nicholas church. “No,” Davey sternly said, dismissing the suggestion that his party’s optimism at taking the seat, where it trailed in third place behind Labour at the last two elections and has never got more than 12% of the vote, had been misplaced. “This weather is sending a signal that change is going to happen. And the change is in favour to us winning,” he said. Davey, sitting in the driver’s seat as the rain beat down on the windscreen of the stationary car, claimed that the party was “in with a huge chance” even though, in normal circumstances, it would be a huge majority for either main opposition party to overturn. He told the Guardian: “We need a much lower swing to win this byelection (23.6%) than what we historically achieved in Cheshire and Amersham. And from the conversations we’ve been having, it’s clear locals are fed up of the Tories and with having an absent MP. “I might get told off for not managing expectations but we’ve got a huge shot at this. I’m extremely confident but am not complacent.” Constituency level MRP polling by Savanta, however, suggests that Labour could win the seat with 41% of the vote at a general election. But the pollsters acknowledge the byelection picture could look quite different as Dorries’ former constituency “feels more like a Lib Dem target” than a Labour one in reality. In contrast to the bullishness of the Lib Dems, it is the Labour party that is managing expectations here, an approach many Labour frontbenchers believe worked for them in the run-up to the local elections in May. Rachel Hopkins, Labour MP for Luton South who is managing the party’s regional campaign, admits it has a “difficult task ahead” to overturn the Tory majority but is confident the party has a chance because people are fed up with the Conservatives. The party hasn’t yet unleashed the scale of campaign already committed to by the Lib Dems but have been hitting the phones relentlessly, which they say gives a more realistic idea of how voters are feeling, particularly in Flitwick, one of the seat’s larger villages. “We haven’t heard anyone mention anything about the Liberal Democrats. They do mention how fed up they are with the Conservatives and are thinking about switching,” Hopkins says. “It’s not going to be easy but we’re in it to win it. We’ve come second in the last general elections and while lots of people voted for the independents at the locals, at parliamentary level those independent votes switch to the most credible opposition, and currently that is us”. Voters in Mid Bedfordshire are not shy of tactically voting if it means getting the “wrong person out and the right person in”, local Mickey O’Rourke, 55, says in the Bumble Bee pub in Flitwick. He has always voted Labour at general elections, but switches when it comes to locals or byelections. “My Labour votes began when I lost the home I was living in with my family,” he says. “It’s always been a battle in this area that isn’t Labour supporting but the mood has never been lower here. Everybody is fed up. The country is absolutely broken.” He gets his wallet out. “Thirty years ago, sitting in this pub with you I’d be able to show my wallet packed with wads of cash. Now look, I’ve just one £10 note to get me by. I’ve got to pay for prescriptions, I can’t see a doctor any more, we just can’t get anything.” Reflecting on Dorries, he adds, “I’ve never seen her here,” and he’s lived in the area for his entire life. “She’s too busy writing novels than spending time helping the locals. I’ll vote for the Lib Dems at this byelection, unless Labour shows their candidate is best placed to win this and get the Tories out.” Former jockey Robert Mason, 90, out for a walk in Flitwick, says many people he knows admit to voting tactically in the area, but it will always be the Conservatives for him, despite anger towards Boris Johnson. “Us old racers always vote blue, it’s what we do. I’m just ashamed of Boris Johnson he let us down over Partygate, and even more so because he still doesn’t acknowledge the wrong that he’s done.” He made no mention of Rishi Sunak. “Of course Boris said he’ll be back but it’s like someone going to prison. They definitely will not have a comeback. Boris has ruined it for himself.” Back by St Nicholas church, Davey ruled out any informal pact with Labour in the seat, where one of the parties would not campaign particularly hard so the other could win, and avoid splitting the anti-Tory vote. He says that if, by chance, he were to pick up a phone call from Keir Starmer, “We’d have a civil conversation. But I know he wouldn’t ask me to make a pact because he knows we’ll fight just as hard.”