According to a report by UK newspaper The Times, the gang hacked into private bank accounts and used confidential customer details to order new debit and credit cards which were used to buy expensive jewellery, electronic goods and euros.

Detective constable Keith Harrington from the Dedicated Cheque and Plastic Crime Unit told reporters that the thieves used a method called 'account take over' to gather enough private customer data to convince a bank that they were the legitimate account holders before ordering a new card and PIN.

Harrington says one case involved the gang using a technique called 'social engineering' where a gang member called staff and feigned memory loss in order to get customer account data.

Barclays Bank has managed to intercept much of the fraud and is believed to have stopped at least £500,000 being stolen from clients, says The Times.

The report says in one case the gang managed to acquire enough data about one victim to have £60,000 transferred from his mortgage reserve account to his current account, which it then stole.

Research released today by Internet security software makers AVG has found that around one third of Brits have experienced some kind of cyber-theft activity over the Internet, including fraudulent e-mails, credit card fraud and unauthorised bank transfers.

However the survey of more than 1400 regular Internet users by online market research firm Tickbox, found that only five per cent have had banking passwords stolen, four per cent has experienced credit fraud and one per cent have had bank details stolen.

Despite this, 43% of respondents feel they are most likely to fall victim to cyber theft, compared to 29% for burglary, 18% for assault and 11% for robbery.

"While the risks of theft over the Internet are real it is important to keep it in perspective," says Larry Bridwell, global security strategist, AVG. "There are a number of things you can do to cut down the risks. These range from making sure you have Internet security installed and regularly updated on your computer."

The research found a high proportion (90%) of respondents had some form of threat protection on their computer, although a third of respondents were not convinced they had adequate measures in place to protect themselves. Just three per cent said they used no protection at all.

Some 25% of respondents also claimed there is not enough information available on cyber theft to adequately protect themselves from it.