First-time buyers who struggle to afford a mortgage “can tap into the flexibility” offered by marathon terms to cut their mortgage costs, according to Moneyfacts data.  

Mortgage borrowers could save £255 per month by choosing a 40-year term, compared to a 25-year term deal when borrowing £250,000, based on the data firm’s average mortgage rate of 5.05%. 

These borrowers could then choose to overpay their 40-year mortgage, as and when they can afford to do so, reducing the mortgage term “without being on the hook for a higher repayment every month,” the firm says. 

It points out that a regular overpayment of £200 per month on a £250,000 mortgage can shave almost 13 years off a 40-year term, and save more than £123,000. 

However, critics of marathon mortgages, of 30 years and over, argue that these deals with longer monthly repayments incur considerably more mortgage interest. 

Over a million new mortgages have been issued since the end of 2021 with terms running past pension age, the consultancy LCP estimated in data published in December. 

The consultancy added that over the last two years, the growth in marathon mortgages seems to have happened “primarily at younger ages”, with a 30% increase in the absolute number of under-forties taking out mortgages set to run into retirement. 

LCP added: “There is a risk that these groups will not be able to afford to service a mortgage once they retire and will raid their pension savings to clear their mortgage, leaving them with less to live on in old age.”    

Moneyfacts finance expert Rachel Springall says: “As consumers work for longer, it’s easy to see why the majority of mortgages, around 85%, allow them to push their term to 40 years.  

“Those prioritising their homeownership plans over their pension may well choose a longer-term mortgage to more comfortably afford mortgage payments.  

“However, being asset rich and cash poor in retirement can lead to borrowers paying their mortgage for longer, incurring more interest and eventually they may turn to equity release to boost their disposable income.” 

Springall adds: “A maximum mortgage term of 25 years would have been relatively standard in the past, particularly when house prices were lower, but the majority of first-time buyers, around 68%, are now taking out mortgages with a term of 30 years or more, according to the Financial Conduct Authority. 

“Affordability remains a key issue and it’s stretching new buyers, with the Bank of England noting the average deposit paid by first-time buyers was around 60% of their household income in 2024.”