A spokesman for the company said: “Offering choice to our customers is important to us and that includes providing the option to pay monthly for their insurance.

“As we strive to deliver good customer outcomes, we are working to reduce our APRs across a number of our brands as part of our ongoing review process.”

A handful of insurers did not respond to Which?’s survey. Those that did included the AA, Hastings Direct, and Santander, all of which charge just under 27pc interest on car insurance monthly payments.

A spokesman for AA Insurance Services said: “The AA remains confident that we offer a fair and affordable way for people to pay for their home and motor insurance.

“We are disappointed that some insurers, especially those with higher rates, decided not to participate in this survey. Their cooperation would have been beneficial so that consumers could see all the options open to them.”

Which? is now calling for the Financial Conduct Authority to “end this injustice” by cracking down on providers charging higher than average interest rates.

Rocio Concha, the group’s director of policy and advocacy, said: “Many customers who pay for home or car insurance monthly don’t do so out of choice, but out of financial necessity. That these same customers can end up paying over the odds compared to those who pay for cover annually is blatantly unfair.

“Car and home insurance policies aren’t nice-to-haves, but essential for motorists and homeowners. It’s high time for the FCA to take meaningful action against firms that continue to charge high rates and end this injustice.”