The popularity of broadband services is helping online sales

Some £4.5bn was spent last month, a 75% rise compared with January last year, said industry body the Interactive Media in Retail Group (IMRG).

Sales were dominated by electrical goods and clothes, which each saw a year-on-year rise of about a third.

But the amount spent fell from the record level seen during the pre-Christmas rush in December.

The equivalent of £74 for every person in the UK was spent online in January, the IMRG Capgemini e-Retail Sales Index found.

Bumper sales

"The index shows that January sales are as large a phenomenon online as they are on the high street, with the overall online market continuing to show strong growth," said Anthoula Madden, vice-president at Capgemini UK's consumer products and retail team.

"The high growth in electricals and clothing suggests that much of this spending is being driven by shoppers treating themselves to the items missing from their Christmas stockings."

The growth in sales volume over the last three months was more than double that of the same period last year. It was at the highest level since January 2003, the index based on about 60 online retailers found.

Sales from the electrical sector in January 2007 rose by 38% compared with the same month last year, while clothing was up by 32%, health and beauty by 18%, and beers, wines and spirits by 9.8%.

Bargain drive

In separate research, consumer group Which? found that high-value purchases could often be found cheaper online.

Which? found savings were available for cars bought online

Its survey of internet car brokers found average savings of 11% on the list prices of 15 new cars.

Researchers said they found the going tough, claiming sales staff were often unprofessional and inefficient.

But they found savings of £2,994 on the list price of a Mercedes C-class, while the Renault Clio 1.5 supermini was £2,550 cheaper online.

Richard Headland, editor of Which? Car, said: "We found that shopping around online is simpler than negotiating with dealers yourself and, in most cases, we obtained a better price.

"Buying through a broker also means you don't have to haggle with pushy salesman. But if you choose to buy from a main dealer, an internet quote can give you the upper hand."