Virgin Media has been ordered to encrypt all portable mobile devices after it was found to have breached the Data Protection Act in losing an unencrypted disc.

The Information Commissioner's Office (ICO) gave the order after investigating the loss of the disc, which contained personal details on customers that signed up to Virgin Media services in Carphone Warehouse stores from January this year.

"The Data Protection Act clearly states that organisations must keep personal information secure," said Mick Gorrill, assistant commissioner at the ICO.

"Virgin Media recognises the seriousness of this data loss and has agreed to take the immediate remedial action that we have outlined in order to protect its customers' personal details."

Any company processing personal information on behalf of Virgin Media must also use encryption software, a requirement which must be clearly stated in all contracts.