Mortgage SHOCK: Homeowners could be overpaying by more than £4,000 a YEAR – this is why

A further four in 10 (41 percent) of 3,500 survey respondents only knew the approximate figure.

The research revealed a quarter of those who took part were on their mortgage lender’s standard variable rate (SVR), usually costing more than other products available from the same provider.

Just over half (55 percent) of homeowners were on fixed rates, while 10 percent were on trackers and five per cent were on discount rates.

The findings showed that borrowers with an average-priced home could end up paying as much as £347 a month (over £4,000 per year) more on their lender’s SVR. 

However, homeowners in London could be overpaying by even more than this, with the cost of an SVR mortgage being as much as £727 more each month - over £8,700 per year.

Those on SVR who had been on the same mortgage for at least five years, said it either was not worth the hassle or claimed they had never thought about switching.

David Blake, Principal Mortgage Adviser, Which? Mortgage Advisers, said: “I would urge anyone with a mortgage to check what interest rate you’re on and whether you’re paying more than you need to.

"The remortgage market is highly competitive at the moment, so there’s a good chance that remortgaging will save you money.

“Speaking to an independent mortgage adviser is a great place to start to find out your options.”

Londoners and 18-24 year olds were most savvy when knowing their mortgage rate, with 80 percent and 74 percent knowing the exact or approximate figure respectively.

Homeowners in Wales fared the worst with their knowledge, with just one in five knowing the exact figure.