Online mortgage broker Trussle is calling for the introduction of a mortgage switch guarantee, similar to what exists to protect consumers in the energy market.

It claims borrowers who switch to cheaper deals could save £4,900 per year in interest charges, but many borrowers do not understand the switching process.

The energy switch guarantee promises customers who find a new deal that their move will be free and complete within 21 days.

Ishaan Malhi, chief executive of Zoopla-backed Trussle, said similar pledges would help tackle a lack of communication and transparency, as well as inertia among mortgage borrowers, which sees many sit on their highly priced standard variable rate (SVR).

The platform claims a more transparent, faster and simplified switching process could help save the 3m people on SVRs some £15bn.

The  figure is taken by using January’s average house price of £218,000 and assuming a 60% loan-to-value mortgage, resulting in a £130,800 home loan.

The average SVR in January 2017 was 4.77%, and the best two-year fixed rate was 0.98% from Yorkshire Building Society.

This loan at 4.77% would have £6,178 interest owed in the first year, while the borrower on the fixed rate would have paid £1,261, a difference of £4,917.

This comes to £14.75bn when multiplied by the 3m SVR borrowers.

Malhi said: “Millions of home owners are collectively losing billions of pounds because switching mortgages isn’t clear or simple. The mortgage switch guarantee will help put an end to this unfairness.

“We’ve spent the best part of a year speaking with thousands of borrowers and meeting with industry leaders from across the market to identify this ambitious but necessary set of standards.

“Thankfully there’s already consensus among senior industry figures that many aspects of the remortgage market are in need of improvement. But for the mortgage switch guarantee to be a success, it will need to be widely adopted by lenders and brokers, and supported by regulators and government. We’ll therefore be speaking with and listening to feedback from these key groups in the coming months.

“The energy switch guarantee, introduced last year after more than a decade of lobbying and hard work, has already helped 5m energy customers save an estimated £1bn.

“The impact of the mortgage switch guarantee has the potential to be 15 times greater, which is why we won’t be slowing down our efforts to deliver a fairer mortgage market for home owners across the UK.”