A disgruntled teenager who sent 5 million emails to his ex-employer that wreaked havoc to the company's servers has walked free after a judge declared he didn't break a government act that attempts to stop computer misuse.

District Judge Kenneth Grant ruled that the youth, who can't be named for legal reasons, had not broken the Computer Misuse Act, under which he was charged.

The defence counsel argued that sending a flood of unsolicited emails would not cause unauthorised access or modification, as the email server was set up for the purpose of receiving emails.

In a written ruling, Judge Grant said: "In this case the individual emails caused to be sent each caused a modification which was in each case an 'authorised' modification. Although they were sent in bulk resulting in the overwhelming of the server, the effect on the server is not a modification addressed by section 3 [of the CMA]".

The Computer Misuse Act, 1990 was passed to deal with the problem of hacking of computer systems.