Mortgage customers seeking to cope with rising interest rates should think small, according to online mortgage firm mform.co.uk.

Smaller building societies currently dominate the best buys for all two, three and five year deals based on the total cost that customers would pay, including monthly repayments, fees and charges.

Its analysis shows that for each category of two-year, three-year and five-year deals, smaller building societies make up at least eight out of the top 10.

The only High Street name to make the top three in any of the categories is Alliance & Leicester with a five-year discounted variable deal offering an initial rate of 5.13 per cent.

The results show that building societies including Beverley, Darlington, Earl Shilton, Furness, Holmesdale, and Marsden are currently all offering deals which put them ahead of big name lenders.

Eamonn Rice, mform.co.uk: "Borrowers looking for the cheapest deals should widen their horizons if they want to save money."

Eamonn Rice, mform.co.uk chief executive, said: "Borrowers looking for the cheapest deals should widen their horizons if they want to save money.

"Smaller societies are competing strongly and offering excellent deals. It is striking that they dominate the best buy lists across two, three and five years at a time when the 25 biggest brands account for around 94 per cent of mortgages advanced.

"Researching the whole market should mean just that and regional societies are a vibrant part of the mortgage market. Borrowers who reject smaller lenders because they are not familiar with the name are missing out."

Deals on offer include Marsden Building Society's five-year discounted variable rate with cashback. A borrower taking out a £150,000 loan for a £200,000 house purchase would pay £53,230 over five years on a repayment basis. The best deal on offer from a major lender would cost £54,206 - an extra £195 a year over the term.

On three-year deals, Furness Building Society offers a discounted variable rate of 4.99 per cent. A borrower taking out a £150,000 loan for a £200,000 house purchase would pay £32,421 over the term on a repayment basis. Someone picking the best deal from a major lender would pay £34,151 - an additional £576.40 a year.

And on two-year deals, Newcastle Building Society offers 4.65 per cent. A borrower taking out a £150,000 loan for a £200,000 house purchase would pay £21,517 over the first two years on a repayment basis. The extra paid by a borrower choosing a major lender would be £341.50 a year for a total of £22,200.

Restricting the search to fixed-rate products did little to raise the profile of the well-known mortgage providers. NatWest did lead the two-year results but the next four lenders to appear were all regional building societies and the three and five-year fixed rate tables were topped by Darlington and Coventry Building Societies respectively.