A survey by Santander Mortgages found that one in five mortgage holders overpay every month. That equates to 2.5 million people who each overpay an average of £181 every month.

Another six per cent make a one-off overpayment on their mortgage once a year and a further nine per cent don’t regularly overpay but have done so once in the past 12 months.

Those who have made a one-off overpayment in the past year – nearly two million people -overpaid an average of £1,919.

In total a third (34%) of those with a mortgage make some form of overpayment, whether monthly or via one-off payments.

The research found that 13% of people who overpay every month started doing so in the past six months, 24% within the last year and 54% within the last two years to make the most of low interest rates.

However, many homeowners do not know they can overpay their mortgage. One in four Brits with a mortgage (23%) have no idea if their mortgage provider allows overpayments at all and a further 14% say their provider allows overpayments but aren’t sure if they charge for them. Another 8 per cent say their mortgage provider definitely charges customers for making overpayments.

Santander’s research reveals that of those people who don’t tend to make mortgage overpayments, over a third (36%) say they could afford to, by an average of 18% extra.

Phil Cliff, director of Santander Mortgages, said: “If you overpay on your mortgage you will pay less interest over the full term, so it’s a good thing to do if you can afford to. Nearly half of those people who have never overpaid on their mortgage still put money into savings each month, and given the average interest rate on these people’s savings accounts is just 1.6 per cent, in the long-term they may be better off using this money to make mortgage overpayments instead.”