Kensington’s analysis of government data shows 17.7% of UK workers – the equivalent of 5.49 million people – receive overtime payments which could be worth up to £3,000 a year for someone working five hours overtime a week.

Th research found that men are more likely to receive overtime pay than women; the analysis shows 22.3% of male workers earn overtime pay compared with 13.2% of female workers.

In addition, there are major regional differences across on the country on how many workers receive overtime pay – employees in Aberdeenshire are the most likely to receive overtime with 28.8% of workers qualifying compared with just 9.6% in Windsor & Maidenhead.

Kensington is highlighting the importance of overtime payments to household incomes as it warns that many mortgage lenders may not count overtime payments when deciding whether to lend to borrowers. The ONS data shows that overtime makes up 2.7% of total average earnings.

However someone on average weekly earnings of £518 working a 37.5 hour week would earn more than £3,000 putting in five hours of overtime for 45 weeks which can add substantially to their ability to borrow and afford a home.

Keith Street of Kensington said: “Many lenders will focus on basic pay and will not fully account for overtime or other regular payments in affordability their calculations.

“This can have a major impact someone’s ability to borrow enough to buy a home if their total income includes regular overtime payments and, as our research shows, it could prove a barrier to more than five million people.

“Kensington aims to treat customers as individuals. Every application is assess by an experienced underwriter and we do not simply reject potential customers on the basis of standard checklists.”