Santander says its mortgage customers have overpaid £335m on their mortgages so far this year – more than £47.5 million a week.

The bank points out that these overpayments, which are 50% higher than the overpayments made in the same period last year, can have “a significant impact” on the interest homeowners pay across the life of their mortgage.

It says a customer currently holding a £200,000 mortgage over a 25-year term could save £877 in interest and become mortgage-free four months earlier with a £10 a month overpayment.

It adds that customers who can afford a £100 regular monthly overpayment will save £7,642 in interest and take more than three years off the life of a £200,000 mortgage.

The bank says that a £5,000 one-off payment on a £200,000 mortgage would save £3,181 in interest across the life of the 25-year loan.

However, some brokers think that the high rate of overpayments may fall, as the cost of living is set to rise later this year.

Earlier this month, the Bank of England doubled the base rate to 0.5% from 0.25%, the second rise from its historic 0.1% low in three months.

The Bank has signalled more rises may be on the way to combat inflation, which hit a 30-year high of 5.5% this week, with the central bank forecasting it will peak at 7.25% in April.

Households also face a triple-whammy of rising bills in April.

Electricity and gas bills for a typical household are set to jump by £693 a year in April, a 54 per cent increase, after regulator Ofgem raised the price caps energy firms are subject to earlier this month. Global wholesale gas prices have risen fourfold over the last 12 months, Ofgem said.

Also, a national insurance tax rise for employees, employers and the self-employed will see them all pay 1.25p more in the pound. It will mean a worker on £20,000 a year will pay an extra £89 in tax, while someone on £50,000 will pay £464 more.

And council taxes are set to rise in most parts of the country in April. Rises will vary across regions but the Institute of Fiscal Studies says a 5% rise, to keep pace with government funding shortfalls and post-pandemic recovery spending, would result in bills rising by £220 a year by 2024-25.

Your Mortgage Decisions director Dominik Lipnicki says: “The rises that are coming will lead to the greatest of living crisis in decades. That’s why I think overpayments of the rest of this year will revert to more normal levels, or come in slightly lower in 2022.

“The national insurance rise will also affect employers, and this may impact what they hand out in pay rises, further hitting household budgets.

L&C Mortgages associate director communication David Hollingworth adds: “It might seem surprising that borrowers have ramped up their overpayments on the mortgage as we enter into a period when living costs are soaring.

“However this is likely to be driven by homeowners that have been able to save more as a result of working from home and the inability to spend as much over lockdown periods. 

“It looks like they are deploying those savings to reduce their liabilities which should, in turn, help them contend with a higher rate environment in future.

“The benefit of ad hoc overpayments is also in the flexibility it gives consumers, overpaying when they can but having the option to pull back if monthly budgeting pressure demands it.

“If the cost of living keeps on climbing then it may curtail the ability to keep up big overpayments but these figures show that borrowers are well aware of what may be coming and are taking positive action to improve their position.”

The average rates for two-, three-, five-, and 10-year all lifted, according to fresh data from Moneyfacts.

The average rate for a two- and three-year fix went up 5 basis points each, to 2.55% and 2.61%, respectively. The average rate for a five-year fix lifted by 7 basis points, to 2.82%, while the average rate for a 10-year fix edged up by 1 basis point to 2.79%.