The Liberal Democrats are to launch attack adverts in Blue Wall seats targeting homeowners' fears of rising mortgage payments following the mini-Budget, The Telegraph can disclose.
The advertisements - which will be on social media and pushed through residents' letterboxes - are being used after an analysis by the Liberal Democrats suggested that traditional Conservative heartlands in the Home Counties will be among those hardest hit by higher interest rates.
It forms part of an effort by the party to pile pressure on electorally vulnerable Tory MPs to rebel against measures such as the scrapping of the 45p additional rate of income tax.
According to the analysis, eight of the 10 areas in England with the highest proportion of mortgage holders are in the Home Counties, including Blue Wall battlegrounds where the Liberal Democrats pose the main threat to Tory incumbents.
Berkshire is the county set to be hardest hit, with its local authority areas of Bracknell Forest and Wokingham having the highest proportion of mortgage holders in the country.
In Bracknell Forest, 37.2 per cent of homes were owned with a mortgage in 2020, while in Wokingham the figure is 37 per cent.
Wokingham has been represented since 1987 by John Redwood, the veteran Tory backbencher, who is a vocal supporter of Liz Truss's tax cutting policies.
His majority fell from 18,798 in 2017 to 7,383 in 2019, with the Liberal Democrats in second place. At the local elections in May, the Tories lost control of Wokingham Borough Council to a Liberal Democrat-led coalition.
Across the country, 28 per cent of homes are owned with a mortgage.
Surrey is also among the counties with a high proportion of mortgage holders. Michael Gove's Surrey Heath seat is in the top 10 areas for the highest rate, with 35 per cent of homes owned with a mortgage.
The Liberal Democrats' campaign will also target voters in constituencies such as Guildford, Hitchin and Harpenden and Cheadle.
In Guildford, Angela Richardson had a 3,337 majority over the Liberal Democrats at the last election. Hitchin and Harpenden is represented by Bim Afolami with a 6,895 majority, and Cheadle by Mary Robinson, who has a 2,336 majority.
The Liberal Democrats claim that the average household on a single variable rate mortgage will pay £2,106 more annually if interest rates rise to five per cent. Those on an average tracker mortgage would pay £3,400 more per year.
However, the Tory MPs could be insulated from some of the political pressure because of the support they enjoy from owners who have paid off their mortgages. It has been estimated that nearly half of Tory voters at the last election owned their home outright.
Daisy Cooper, deputy leader of the Liberal Democrats, told The Telegraph: "Liz Truss has betrayed homeowners. I really feel for first-time buyers who have saved massive deposits to only now be hit with a monster rate rise.
"This is all the Conservative government's fault. They chose to max out the country's credit card despite knowing full well it would send the financial markets into turmoil."