Half of home wi-fi networks 'hacked in less than five seconds'

Of the 40,000 networks identified in the six cities, just under 20,000 had no password or the most basic form of security encryption, the research for card protection and insurance company CPP found.

In the “ethical hacking” experiment, researchers spent half an hour in each city using freely available software to use as many unsecured wireless connections as possible.

Almost a quarter of the private networks (9,249) had no password, despite 82 per cent of Britons believing their network is secure.

But the study found even password-protected networks were not secure, with hackers able to breach a typical password in seconds.

The hackers were also able to “harvest” usernames and passwords at a rate of more than 350 an hour when sitting in town-centre coffee shops and restaurants.

CPP identity fraud expert Michael Lynch said: “This report is a real eye-opener in highlighting how many of us have a cavalier attitude to wi-fi use, despite the very real dangers posed by unauthorised use.

“We urge all wi-fi users to remember that any information they volunteer through public networks can easily be visible to hackers. It’s vital they remain vigilant, ensure their networks are secure and regularly monitor their credit reports and bank statements for unsolicited activity.”