Another threat is from hostile governments. The US defence department believes 120 countries pose a serious threat to cyber-security. They include Libya, Iraq, Croatia and Serbia. The Chinese are thought to have created military regiments dedicated to cyber-warfare. Critics say British authorities have yet to establish an effective, single body to deal with the threat.
Many experts also say the security agencies are looking in the wrong place.
Terrorists make targeted demands and like a high degree of control over their operations. The standard profile of a virus writer is a young man with a grievance. He is often a professional programmer who feels his skills are not being recognised. Hidden behind a series of fake and anonymous e-mail accounts the virus writer is rarely detectable. But this weekend investigators seemed confident they were close to catching the man behind the love bug.