Which? Has found that 33% of homeowners are unaware of the interest rate on their mortgage repayments. A further 41% of the 3,500 survey respondents only knew the approximate figure of their mortgage interest rate, with around a quarter of respondents saying they were on their mortgage lenders standard variable rate (SVR) - typically costing more than other products available from the same provider. 

55% of homeowners were on fixed rate rates, 10% were on trackers and only 5% were on discount rates. In its entirety, the survey found that borrowers with an average priced home could end up paying what equals £347 per month on their lenders SVR. Homeowners in London are even worse off, paying an extra £727 a month or £8,700 per year. 

Those who had been on SVR for at least five years admitted that it was either too much hassle for them to move or that they hadn't even thought about it before. 

Principle Mortgage Adviser at Which? Mortgage Advisers David Blake says, "The remortgage market is highly competitive at the moment, so there's a good chance that remortgaging will save you money".

Londoners and younger borrowers in the 18-24 age bracket were most clued up on their mortgage rate, with 80% and 74% knowing the exact or approximate figure respectively, whilst only 1 in 5 homeowners in Wales knowing their exact figure.