Nearly half of all home Wi-Fi networks in the UK could be hacked within five seconds, according to CPP.

The life assistance company employed the services of 'ethical hacker' Jason Hart to roam six major cities across the UK and use specially developed software to identify home networks that were at risk of Wi-Fi jacking.

Wi-Fi jacking is a technique used by hackers to piggyback on a net connection, and allows them to illegally download files, purchase illegal goods or pornography or even sell on stolen goods without being traced. It also allows them to view the private transactions made over the net, providing them with access to passwords and usernames that can subsequently be used to commit identity fraud.

CPP's research, which has been conducted ahead of National Identity Fraud Prevention Week, revealed 40,000 home Wi-Fi networks were at risk.

CPP also said that despite the fact that 82 percent of web users believe their Wi-Fi connection is secure, nearly a quarter of private wireless networks are not password-protected.

Furthermore, around one in six web users (16 percent) say they regularly use public networks. During his research, Hart was able to 'harvest' usernames and passwords from public Wi-Fi networks at a rate of more than 350 an hour.

He also revealed more than 200 web users unsuspectingly logged onto a fake Wi-Fi network over the course of an hour during the experiment, putting themselves at risk from fraudsters who could harvest their personal and financial information.

"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," said CPP identity fraud expert Michael Lynch.

"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."

Hart warned both businesses and individuals to "think very carefully about network security and what information they provide when going online".

See also: 3.7 billion phishing emails sent in the last 12 months