The past two months have seen the gap between the average cost of a personal loan and official interest rates almost double, according to new research.

Although the Bank of England base rate has fallen from 5% to 3% over the period, consumers looking to take out an unsecured loan can expect to pay around 8.46%, up from an average rate of 7.92% in September.

Figures from financial website moneysupermarket.com show that the new average loan rate is now 5.46% higher than the base rate, compared with September when it was only 2.92% higher.

In the past fortnight, three major loan providers have increased their rates by up to 0.3% despite November's 1.5% interest rate cut.

Moneysupermarket.com said that the average personal loan rate was now at its highest level since its records began in March 2003.

The group's head of loans, Tim Moss, said: "Loan costs are often overlooked in the frenzy of a base rate cut, when the focus is on the impact of any rate movement on mortgage payments and savings rates.

"What our calculations clearly show is that the cost of a personal loan is as apparently uncorrelated to base rate as mortgage rates are.

"The key difference though is that mortgages are priced according to Libor (the inter-bank lending rate) rather than base rate - loan rates are not."

Mr Moss warned that average loan rates could increase to around 10% next year as a result of the Competition Commission's recent recommendations on the sale of controversial payment protection insurance (PPI).

The commission called for a ban on the sale of the cover alongside credit agreements, instead saying firms would have to wait for 14 days before they were allowed to contact customers and sell it.

PPI sales are likely to be dented if the recommendation comes into force. Revenue from selling such policies has in some cases been used to subsidise personal loan rates.

Copyright © Press Association 2008