Personal information has been discovered on recycled computer hard drives used in repaired PCs, prompting experts to advise that hard drives should never be reused in this way.

Phil Clayton approached vnunet.com after discovering pictures of someone else's children, along with web documents and emails, on a recycled hard drive which was installed in his machine when it was sent away to be repaired.

Clayton had sent his PC for USB port repairs, but discoverd his hard drive was also replaced by Mastercare, the aftersales repair and customer support company owned by the Dixons Group.

Clayton complained because the replacement drive was of a lower specification than his original. When Mastercare did not believe him, he used a data restore program to prove it. It was then that he found information left on the drive by the previous owner.

From this information, he was able to track down the drive's original owner, whose PC had been written off by Mastercare as unrepairable.

Both men were deeply concerned about privacy issues and the implications of strangers being able to access personal data. But current data protection legislation had not been violated, according to a leading lawyer.

"The Data Protection Act does not cover domestic personal data on home PCs. Neither is there a law that covers overall right to privacy in this country," said Jon Fell, a partner with law firm Masons.

"And unless there was a specific contract signed with the company to destroy the data, which if not followed could be breach of contract, the duty of care remains with the owner."

Dixons' terms and conditions for its warranties do state clearly that the company uses refurbished components in repairs. Dixons said it uses what is known as low-level formatting techniques to wipe data from hard drives and other memory devices.

It has now agreed to review its data wiping procedures and is trialling a number of different methods.

But the ease with which Clayton was able to retrieve data, using freely available software, illustrates how difficult it is to delete information.

Clive Carmichael-Jones, a data recovery expert with forensic computing company Vogon, said data that people think they have eradicated can often be retrieved.

"There are a whole range of techniques used to remove data - some good, some not so good. But even the most complex and high-level techniques are not necessarily foolproof," he said.

"It is almost impossible to get rid of data on hard drives and we would never recommend reusing them."