There is a logical attraction to skipping the chaos of the high street to shop online for post-Christmas bargains but every credit card purchase leaves consumers at risk.

Internet fraud has grown as relentlessly as online commerce and an estimated 3.5 million people in Britain were the victims of some form of cybercrime last year.

Card fraud affected 1.7 million people according to getsafeonline.org, a joint government and Serious Organised Crime Agency body.

An investigation by The Times this month discovered that fraudsters were selling British credit card numbers for as little as £1 each.

Criminals can use this information to go on a shopping spree before banks or cardholders realise they are being targeted. Online card fraud rose 16 per cent in 2006 and is now costing banks more than £212 million.

The introduction of chip-and-PIN has enabled banks to cut face-to-face fraud by 47 per cent, but the rise in internet fraud has wiped out these gains. Internet users also continue to fall victim to phishing scams, which lure unsuspecting computer users into revealing bank details, including account numbers and passwords.

Some of the latest are highly sophisticated and use mirror web addresses to make fake bank messages look real.

Security consultants are also concerned by the loss of confidential data by government departments.

The latest figures from Cifas, the antifraud group, show that identity fraud is one of the fastest growing areas of crime. The number of cases rose 9 per cent to 125,483 in the first nine months of this year compared with the same period in 2006.

People in London are the most likely to suffer from identity-theft crime, followed by Brighton, Grays, in Essex, Southsea and Swindon. People should shred documents containing personal information and ignore unsolicited communications from online banks.