Google said on Friday it had not kept its promise to delete all the personal data its Street View cars collected in Britain and other countries in 2010.

In 2012 Google admitted its vehicles used to photograph neighborhoods to create street level images had accidentally collected data from wireless networks used by residents in more than 30 countries.

The failure to comply with a promise to delete all the data was notified to Britain's Information Commissioner's Office (ICO), which said the fact that the data still existed appeared to breach an undertaking signed by Google in November 2010.

"Earlier today Google contacted the ICO to confirm that it still had in its possession some of the payload data collected by its Street View vehicles prior to May 2010," an ICO spokesperson said. "This data was supposed to have been deleted in December 2010. The fact that some of this information still exists appears to breach the undertaking to the ICO signed by Google in November 2010."

ICO told Google to supply the data to it immediately, so that ICO could subject it to forensic analysis before deciding on the necessary course of action.

"The ICO is clear that this information should never have been collected in the first place and the company's failure to secure its deletion as promised is cause for concern," ICO added.

Google was fined $25,000 in April for impeding a U.S. investigation into Street View data collection.