In a bid to improve his party’s fortunes in “blue wall” seats where Tory voters have shown a willingness to switch parties, Davey said there was now a “mortgage penalty” on some landlords after the mini budget. He said there are now people who are “worried sick about how they’re going to get by or even afford to stay in their homes.” In an economy speech on Sunday, he will call for a temporary £3bn mortgage protection fund to help homeowners who have seen their mortgage repayments rise by 10%. It says it could be paid for by reversing cuts to bank levy and bank surcharge from 2016. “The Conservatives have crashed the economy and this has added hundreds of pounds to the monthly mortgage payments of millions of people,” he said. “Something needs to be done, particularly for those who are really struggling or at risk of falling into arrears or even facing recovery. “The banks have to pay their fair share. We bailed them out during the financial crisis, so they should be supporting struggling families in this crisis. It seems like the right thing to do.” He insisted the program would be “well-targeted” and aimed at the quarter of households struggling most with costs. He said that while it had not helped tenants, the Lib Dems had already backed a range of measures designed to give them more certainty and control over their home. The party pointed to figures suggesting the average two-year fixed rate has risen from 4.24% at the start of September to 6.55% now, adding around £1,800 to a typical household’s annual mortgage bill by the end of 2023. Around 1, 2m households with flexible rate mortgages have already seen their monthly payments rise, while 1.8m more are on fixed rate deals due to expire next year. “We’re seeing lifelong Conservatives, in all the seats we’re running on the blue wall and beyond, saying the Conservatives were just chaotic,” Davey said. “There is no doubt that lifelong Tories are really reconsidering their votes and many of them are coming to us. I think this is the type of approach that is needed to help these families. Many of them may have voted Tory in the past. Many may vote Lib Dems. But this is exactly the right thing to do.”