Despite high-profile security scares such as the Blaster worm and the latest SoBig variant, almost one-third of small businesses in the UK do not consider antivirus or firewall protection to be important.

According to a poll conducted for BT Openworld, some 28 per cent of companies believe that software solutions for protecting their business from security threats is of no practical use.

The study of 300 small and medium-sized enterprises found that this disregard for IT security was most pronounced among smaller firms that employed fewer than five people.

Neville Manuel, vice president of value-added services at BT Openworld, said: "It's frightening that small companies are ignoring the risks of IT security threats.

"No matter what size business you are, a major security problem could bring all your systems to a halt.

"This can have a serious impact on a business, in terms of lost sales, reduced productivity and damaged reputation. These are all dangers that no company can afford to ignore."