Updates to this story
According to the Daily Telegraph the data is being used on Google's Maps for Mobile application to locate mobile phones such as iPhones in order for users to access information relevant to the area such as restaurants, cinemas, theatres, shops and hotels.
While it was known that Google was collecting the data, it was not known the extent of the situation.The search engine outfit has said that it "mistakenly" downloaded data packets, which may have included fragments of emails and other data, from unsecured wireless networks where they were not protected by a password.
However Google said that other outfits have already mapped wireless networks. An Apple hired outfit Skyhook Wireless has been named as one.
The data, which includes the networks' MAC (Media Access Control) address and SSID (Service Set-ID) number, is publicly available because the wireless network signals extend beyond the property in which they are located.
While the collection of such data using Street View cars across the world has been abandoned, the Daily Telegraph said that its work in Britain is already complete.