Pornography and spam continue to flood email inboxes despite government attempts to stem the tide, according to the internet security and filtering firm Surfcontrol.
New laws passed last December made it a criminal offence, punishable by a fine, to send spam to private email addresses. But Steve Purdham, chief executive of the Cheshire-based company, said yesterday that millions of pounds continue to be spent on distributing racist and sexist material on the web.
"The need to stop porn and spam has increased," he said, with companies becoming more concerned about protecting their systems. Last February a computer virus called MyDoom was released from Russia and infected computers across the globe.
Purdham added that "phishing", where internet fraudsters flood inboxes with fake emails in an attempt to get people's bank details, is also a growing problem.
The increased demand for protection from criminals and internet pranksters is behind the increase in business reported by Surfcontrol yesterday.
In a trading statement the company reported a 21 per cent rise in revenue to $25.8 million (£14 million) over the three months to March.
The company, which has $89 million in the bank, saw business in the United States grow by 17 per cent from last year and by 25 per cent in both Europe and Asia.
Analysts at Corporate Synergy said growth in the United States has been above expectations in what is traditionally a slow quarter for the company.
Shares in the company added 9p to close at 585p.
Purdham added: "There is a general confidence in the economic situation and companies are using their budgets to manage their internet content."
Bosses are becoming increasingly concerned about employees spending company time sending jokes and personal email. Last year Phones4U boss John Caudwell caused controversy when he banned all internal email.
He claimed it cost the business £1 million a month with employees spending three hours a day on email.