Google committed a “significant breach” of data protection laws when its Street View cars “mistakenly” collected people's email addresses and passwords over unsecured WiFi networks, the Information Commissioner has ruled.

However, the company escaped a fine and was asked only to promise not to do it again.

Now a cyber-security expert based in Belfast warned that the information gleaned by Google could be abused if it fell into the wrong hands.

Information Commissioner Christopher Graham said Google had broken the law when devices installed on its specialised cars collected the personal data.

He told the company to delete the information “as soon as it is legally cleared to do so” and ordered an audit of its data protection practices.

The breach occurred between 2008 and May 2010 when Google was photographing streets across the UK, including Northern Ireland.

Dr Sakir Sezer, research director at the Centre for Secure Information Technologies at Queen’s University, explained the implications of the data breach.

“I think what is worrying is that Google has collected information on private WiFi (wireless) access,” he said.

Dr Sezer said Google was not only mapping streets but internet hotspots — places where you can have free wireless internet access.

“I believe Google will publish maps on free public hotspots. But by collecting data on public WiFi, they have also collected private WiFi information.

“The worst-case scenario is that someone who discovers you have open WiFi could drive to your house, sit in their car, and distribute spam or use your internet access for illegal dealings.

“They could also extract information to use fraudulently.”