Google has come under fire from the German government after admitting it has been collecting Wifi data as part of its Street View program for four years.
It gathered as much as 600GB of data from Wifi networks in more than 30 countries, including the websites people were viewing and the contents of emails.
In a blog post on Friday, Google said that it was all a complete accident, and apologised for earlier assurances that it was doing nothing of the kind.
"We said that while Google did collect publicly broadcast SSID information (the Wifi network name) and MAC addresses (the unique number given to a device like a Wifi router) using Street View cars, we did not collect payload data (information sent over the network)," said senior VP for engineering and research Alan Eustace.
"But it’s now clear that we have been mistakenly collecting samples of payload data from open (ie non-password-protected) Wifi networks, even though we never used that data in any Google products."
But Peter Schaar, Germany's federal commissioner for data protection, and freedom of information says this explanation won't wash.
"So everything was a mistake, a software bug! The data was collected and stored without the authorisation of the project's managers or even the company's managers. If go along with this story, this means the software was used without having been properly tested beforehand," he says.
"It acquired billions of records unintentionally, without anyone in the company noticing, not even Google's internal data protection officials, who were still defending the company's practices two weeks ago."
Google has promised to delete the offending data in conjunction with regulators, but its actions are likely to bring it under renewed examination by the European Commission.