Companies could find that their IT systems are inadvertently being put at risk through the actions of their employees.

David Emm, a senior technology consultant at Kaspersky, said that as many workers brought to work devices such as USB drives and MP3 players, there was a risk they could infect their firm's IT network with a virus if they connected themto their PC.

He said that it was "unrealistic" to ban employees from doing this and instead said that they should be encouraged to scan them for viruses before they attached them.

Mr Emm added that IT security advice given to employees should be made relevant to the individual. He suggests that, as a way of getting the message across, bosses could highlight the potential security risk someone faced if they used online banking at work.

Research by Websense found that 45 per cent of businesses have had their IT systems infected by a virus.

According to a recent survey by Connect, the two biggest IT headaches for businesses were 'everyday hassles with IT' (37 per cent) and 'security concerns' (32 per cent).