Carphone Warehouse and sister company TalkTalk have repeatedly breached the Data Protection Act, according to the Information Commissioner's Office (ICO).

The two firms broke the law when customer accounts were opened in the wrong name and inaccurate information was then passed on to credit reference agencies and debt collection agencies.

The company failed to protect customers' information adequately, according to ICO assistant commissioner Mick Gorrill.

"Carphone Warehouse and TalkTalk's use of inaccurate and incorrect personal data has caused real damage and distress to customers," he said.

"We have ordered them to take the necessary steps to ensure personal information is sufficiently protected."

Security failings also led to customers being able to view others' account details online.

Carphone Warehouse and TalkTalk have been issued with enforcement notices ordering them to comply with the principles of the Data Protection Act. The ICO continues to campaign to make such breaches of the Data Protection Act a criminal offence.