The mutual says its new rules mean that many clients will see an increase in their maximum borrowing potential, including new borrowers, those looking to remortgage, expats and high-net-worth individuals. 

The new criteria cover loans up to £5m and comes into effect immediately. 

It explains that clients with a household income of £100,000 looking for a residential repayment mortgage on a two-year discount rate could now borrow up to £55,000 more under the society’s new stress testing. 

These figures are based on the mutual’s tier two residential up to £3m two-year discount product, with a rate of 5.49%. 

In recent months, TSB, Barclays, and Nationwide among others, have also eased their affordability rules to allow tens of thousands of pounds of extra borrowing for first-time buyers, home movers and remortgagers.    

The moves from these lenders come after the Financial Conduct Authority said in March that lenders have been “too cautious” in granting FTB home loans under current rules.    

Financial Conduct Authority chief executive Nikhil Rathi told the Treasury Committee that under existing regulatory rules, lenders have a degree of “flexibility” over the stress tests they apply to homebuyers coming to the market for the first time, which they have not exercised. 

Market Harborough’s head of mortgage distribution Iain Smith (pictured) said: “We’re seeing a welcome market shift in how affordability is assessed, and these changes are designed to support more clients with complex needs on top of what we’re already offering, including multi-generational and joint borrower sole proprietor solutions, interest-only deals, and no loan-to-income cap across our products.”