A computer hacker from Eastbourne wiped three years' work from a firm's records after it refused to pay him for a botched job.

Stephen Carey used his home computer to get into the customer files of a sheet metalwork firm and delete the complicated drawings.

Designers at R P Duct Work watched in disbelief as plans for air conditioning units vanished one by one from their screens.

Carey, 28, used his hacking skills to change designs by the firm. He then tried to cover his tracks by deleting files on his computer.

His actions cost the company between £25,000 and £50,000 to put right.

Carey, of Milfoil Drive, Eastbourne, was convicted of unauthorised modification of computer material at the end of a nine-day trial at Hove Crown Court last month.

He was sentenced to 18 months in prison yesterday when a judge told him his actions had been: "malicious in the extreme."

The court heard how Carey worked as a computer engineer for Renaissance Computer Company, of Oaklands Way, Hailsham, when he was sent to R P Duct Work's factory at Diplocks Industrial Estate in Hailsham on April 10 last year.

Carey was asked to update the computer network but made a mess of the job.

He was called back the same day to solve the problem but the email system still failed.

The following day the firm had to pay another expert £80 an hour to put it right.

Bosses refused to pay Carey's bill, the court heard.

But on May 1, staff at Duct Work noticed the drawings directory from the system was vanishing before their eyes.

The firm shut down the system and called their IT engineer. He found someone had broken into the system.

British Telecom's Nuisance Calls Bureau was contacted.

It found the network had been contacted from an outside line nine times between April 30 and May 1, 2001 by one phone number - Carey's.

On May 3, officers raided Carey's home where he was arrested and computer equipment seized.

Carey denied involvement but police found the times of deletion directly corresponded with the time his phone number was connected to Duct Work's system.

The father of one and stepfather of three children finally admitted his role, saying he did not do it for cash and claimed he did not know the firm's files were not backed up.

Judge David Rennie ordered Carey should serve half the sentence and the rest would be suspended after he was released on licence.

Judge Rennie, jailing Carey in the first prosecution of its kind, said: "You are a clever man and a cunning man and I am sure you knew your actions would cause great harm.

"Your actions were malicious in the extreme.

"Computer hacking is a growing menace and a clear message needs to be sent out to other would be hackers that if they attack companies they will be sent to prison for a substantial amount of time."

Duct Work's general manager Ivan Manning declined to comment, saying the company did not want to glorify Carey's crime.