Google's Street View Cars have logged every wireless network in the UK, it has been revealed.
Earlier this month the search engine company admitted it has been mistakenly collecting data from unsecured Wi-Fi networks for three years.
The company said the error came to light after the German data protection authority audited the Wi-Fi data collected by Street View cars for use in location-based products such as Google Maps for mobile.
However, now Google has admitted that as well as collecting snippets of data passed over Wi-Fi networks, the radio aerials on its Street View cars also collected the MAC (Media Access Control) address and SSID (Service Set-ID) number of home Wi-Fi networks, effectively mapping wireless networks across the UK.
The search engine, which has suspended its Street View cars across the world, said it wasn't the first tech company to map wireless networks, and it had not noted house numbers of the networks ensuring they weren't identifiable.
Many privacy campaigners, including Privacy International, are calling for Google to be investigated.
"The ghost of Street View continues to haunt Google," Privacy International told the Telegraph.
"The idea that it can log everyone's Wi-Fi details because it is all 'public' is a bogus argument. It is bogus because of the question of scale and the question of integration with other information which would amount to a huge breach of our privacy," the organisation said.
"There should be a parliamentary inquiry which should question Google and finally get it to explain what it is up to both technically and commercially."
The Information Commissioner's Office (ICO) said it was aware of the issue.
"If we find evidence of significant wrongdoing, we will of course investigate and consider what action should be taken."
See also: Google gets 1,116 UK gov't requests for user data