It comes after research by Lloyds TSB Internet banking revealed that over half of PCs and laptops have been infected with a computer virus.

It also found that one in ten computer owners have never updated their anti-virus software, while a quarter have only updated it once or twice.

One per cent of PC owners confessed that they had no anti-virus software installed at all.

Failure to update anti-virus software and to have a robust firewall can leave computers open to attack from both viruses and hackers looking to obtain personal details, which can then be used to access internet bank accounts.

Matthew Timms, internet banking director, Lloyds TSB, said: \"At Lloyds TSB, we use the highest levels of industry-standard security so customers can access their accounts online with the utmost confidence.

\"But while we are doing everything we can to make our security watertight, we also urge all of our customers to think carefully about the measures they have taken to protect their PC. This means regularly updating their anti-virus software and ensuring they have a robust firewall.\"

The survey also revealed low awareness among computer users about the steps they can take to protect their PCs.

Lloyds TSB\'s tips include keeping operating systems and web browsers up to date by downloading patches from software publishers who may occasionally discover vulnerabilities in their products.

It also suggests using personal firewall software to prevent unauthorised access to PCs, ensuring anti-virus software is kept up-to-date, avoid downloading software from non-trusted sources, and being wary of emails that contain attachments.