The internet worm is now 20 years old, according to a security news provider.

Last weekend marked the first time a virus was given the ability to replicate itself on an individual computer, in turn stopping thousands of Unix-based systems across the world by exploiting their vulnerabilities, computing expert Asavin Wattanajantra revealed.

The Morris Worm, which was named after its creator Robert Tappan Morris, first appeared on November 2nd 1988 and "changed the face of internet security forever", he said.

Mr Wattanajantra added that the experiment led by the coding specialist was more damaging than he had believed, resulting in his sentencing to community service and probation.

The worm was designed to gauge the size of the internet through the self-replicating function, ultimately causing the damage it did.

Research by NewDiligence last week found that the average large enterprise was losing around $125,000 (£77,000) a month to fight against the threat of malware.

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).