Financial search engine moneyfacts.co.uk has suggested that despite a recent spate in the number of mortgage lenders increasing the rates offered on their variable rate products, consumers should not be overly worried at the moment.

The website said that providers such as Abbey, the Royal Bank of Scotland and Standard Life had all introduced a rate rise on mortgages, with Capital Home Loans withdrawing all their tracker products for the time being.

However, Julia Harris, mortgage expert at moneyfacts.co.uk, said it was far from unusual for firm''s to change the specifications of their products and the changes should be taken as a sign the crisis in sub-prime lending had arrived on British shores.

"While lenders could be hedging against the possible uncertainty in the mortgage market, there could also be many other reasons underlying these changes," she said.

"If we start to see more significant and prolonged increases, or standard variable rates begin to rise, then it may be a sign that the market is suffering at the hands of its investors."

Ernst and Young''s Item Club warned today that the impact of current economic turmoil could pose problems for people coming to the end of fixed-rate mortgage deals this year.