Research has revealed that the financial loss to SME's when the next big computer virus hits could be billions

The next big computer virus attack could cost the UK's small and medium-sized enterprises (SMEs) £2.1bn, according to research carried out by McAfee Security.

The research showed that of the 70 percent of SMEs who said they had received a virus, all had lost money and suffered systems downtime as a result.

The average financial loss was £843 per company, equating to a total of £2.1bn, and the average downtime was 7.2 hours -- almost a full working day.

Nearly all the survey respondents agreed that cybercrime is on the increase (91 percent), but 12 percent still have no virus protection in place. Nearly half (43 percent) have no firewall protection from hackers.

Peter Scargill, IT chairman of the Federation of Small Businesses, said: "Many SMEs agree that cybercrime is a serious issue but fail to protect all of their computers or update protection regularly. Viruses or hacker attacks could be disastrous for many SMEs. They must start putting protection in place."

The survey also revealed that many SMEs do not subscribe to the generally accepted rule that prevention is better than cure, and wait until they are infected by a virus before taking action to address their vulnerability.

A third of respondents (32 percent) bought virus protection after they'd been infected by a virus.

Marc Vos, European product manager for McAfee Security, said: "It is very important that SMEs protect themselves against cyber crime properly. Although many have protection, it is useless unless they keep it regularly up-to-date."

He added: "Viruses tend to grab the news headlines but SMEs are often left wide open to other forms of cybercrime such as fraud or hacking. These threats are especially hazardous for high speed Internet users who are always connected and therefore always open to attack."