The data was collected by Steet View cars.
Google is facing a series of international investigations over private information it obtained over families’ use of the internet. The search giant is braced for inquiries in America and Germany after it admitted recording information broadcast via unsecured wireless networks in family homes.
It will not face any action in the UK because the Information Commissioner is satisfied with the company’s promise to delete the data “as soon as reasonably possible”.
But the international inquiries are a fresh embarrassment for Google, which on Friday backtracked on earlier denials that it had stored data collected from wireless networks by its Street View cars.
The company said it used its fleet of camera-rigged vehicles – which provide the 360 degree pictures for its online mapping service – to amass information on Wi-Fi addresses in order to help target its location services.
It admitted that the cars, which have spent two years taking pictures of homes on British streets for publication online, inadvertently recorded short bursts of people’s internet activity while passing by.
Google insisted that the information was collected by mistake, that it was never used and had never been made available to other companies.
But the company now faces questions over its harvesting of the data, which UK authorities said appeared to be in breach of the Data Protection Act.
Peter Schaar, the German commissioner for data protection, said a “detailed probe” was required, while the US Federal Trade Commission was also reported to be preparing an inquiry.
Marc Rotenberg, of the not-for-profit Electronic Privacy Information Center in Washington, told the Financial Times: “This may be one of the most massive surveillance operations by a private corporation that has ever occurred.
“It is unprecedented vacuuming of Wi-Fi data by a private company.”
Peter Barron, a spokesman for Google, said: “We didn’t want to collect this data in the first place and we would like to destroy it as soon as possible.”