Viruses, spam and malicious internet scams transmitted by email all grew sharply in 2002, posing a threat to the smooth running of worldwide email systems, according to security vendor MessageLabs.

The problem of spam, or unsolicited email, has become so bad that the number of spam emails being received will exceed the number of legitimate emails next year, MessageLabs said.

In its review of email threats for 2002, MessageLabs reported that spam already accounts for 30 percent of all email, and that figure is set to rise to 50 percent by July 2003.

But it's not just 'innocent' spam that is on the rise, as email viruses are become more prevalent too. In 2001 one in 380 emails was infected; in 2002 that number had risen to one in 212 and again this is likely to increase again for 2003.

Not only are viruses becoming more frequent, they are also getting more virulent, as MessageLabs found that today's bugs are more technically sophisticated and can expose vulnerabilities in traditional antivirus software. The security firm also saw a sharp increase in the number of blended threats — where spam emails are combined with viruses — and Trojan attacks on both companies and individuals.

If you, like us, do your best to delete any spam or suspicious email, you might wonder why people bother with it. But MessageLab's review also revealed that spam scams can be a lucrative business.

The study found that scams, such as the Nigerian email advance fee con are continuing to proliferate and prosper. This swindle alone is expected to gross $2bn in 2003 (£1.3bn), making it that country's second-largest industry.