A man who admitted infecting thousands of computers world-wide with viruses has failed to have his prison sentence cut.
Simon Vallor created three computer viruses
Simon Vallor, 22, created the viruses at his home in Llandudno, north Wales, and released them on to the internet.
The three "worms" between them attacked 27,000 computers in 42 countries.
Vallor had admitted three counts of releasing a computer virus and was jailed for two years at Southwark Crown Court in January.
But at London's Court of Appeal on Monday Web designer Vallor's counsel, Grant Van-Stone, argued that he did not realise the extent of damage the viruses would do.
Vallor wrote three viruses - Gokar, Redesi and Admirer - which he sent out via e-mail.
The Gokar virus was the most virulent of the three and was still active in December 2002.
Vallor was eventually tracked down in February 2002 by North Wales police, working with the FBI, through his computer name of "Gobo" which he used to send the e-mails.
Mr Van-Stone unsuccessfully argued that Vallor's sentence should be cut because of his relative youth, previous good character and the fact he had co-operated with the police.
But dismissing the appeal, Mr Justice Aikens said that Vallor's crimes were "calculated and disruptive."
The "mass-mailer" viruses were sent as e-mails that were automatically sent to everyone on the computer's address book.
Vallor is thought to have seized-up 27,000 computers across 42 countries.