A quarter of homeowners fear they will lose their homes or default on payments.
Research commissioned by the Liberal Democrats has found 27% of mortgage holders were worried about losing their home due to unpaid bills as interest rates rise.
The Liberal Democrats were setting out their policy for a state-backed mortgage protection fund to stop families falling into arrears.
The estimated £3bn cost of the Mortgage Protection Fund would be paid for through reversing Conservative cuts to the bank levy and bank surcharge taxes since 2016, the party has said.
Households would be eligible if they have seen an increase equivalent to more than 10% of their income, and could then apply for grants of up to £300 a month to help cover the cost of the rise.
