Homeowners whose lenders only pay down the interest on their home loan annually are paying thousands of pounds more for their mortgage than necessary.
Aaron Strutt from mortgage broker Trinity Financial told Thisismoney.co.uk: 'It is pretty shocking that some of the lenders are still calculating interest on an annual basis, particularly as the larger banks and building societies switched to a daily or monthly calculation years ago.
'They made the changes as part of the Treating Customers Fairly drive, which is still regularly discussed within the industry today.
'Some of the lenders have different policies for new and existing customers, so it is worth checking to make sure your mortgage interest is being calculated on a daily basis and settled monthly. It could be costing you a fortune if you are on a standard variable rate or longer-term fixed deal and you make regular overpayments.'