As many as 500,000 homeowners could have squandered as much as £369 each over the past three months alone, simply by delaying remortgaging from their lender’s SVR to one of the many leading headline rates on the market.

This is according to mortgage website, Charcolonline, who recommend homeowners to urgently review their mortgage deals to see how much better off they could be by switching to a more competitive deal.

Homeowners faced a financial shock over the summer, when the plethora of the lowest-ever two-year fixed rates, arranged in the early summer of 2003, came to an end. The difference between the best two-year fixed rate of 2003 and the current average SVR is a staggering 3%, equating to an extra £180 per month.

The current difference between an SVR deal and a market leading remortgage product is 2%. This means that homeowners who still remain on their lender's SVR after just three months have effectively thrown away £369.

Drew Wotherspoon of Charcolonline said: "I am sure the lenders will have benefited from some summer apathy from borrowers who have had rearranging their mortgage way down on the list of priorities."

"Three months is not a long period, yet in financial terms, it simply does not make sense for them to remain on an uncompetitive rate a day longer than they ought to. Whilst they are unlikely to find a deal as good as the ones we saw in the summer of 2003, there are nevertheless some very attractive options in the market."

"A mortgage is most people's biggest financial commitment so there is no room for apathy when it comes to ensuring you are getting the best possible value for money and the first step is to research the market fully for the best deals."

Charcolonline calculate that a borrower continuing to languish on an SVR for a year could waste almost £1,500. "Remortgaging is no longer the arduous task it used to be, and is now a relatively quick and painless process," said Drew Wotherspoon. "But the sooner it is done, the more savings there are to be made."