Almost half of all UK wireless networks are open to attack, according to research from anti-virus company Kaspersky.
The report found that a shocking 49 per cent of wireless networks in London were operating without any encryption.
Tests in the business district in London's Canary Wharf found the area marginally safer, although 40 per cent of wireless networks were still unencrypted.
Kaspersky's research was carried out between 25 and 28 April 2006 in various areas of London, and at the Infosec security conference, with data collected from more than 600 Wi-Fi access points.
"You would expect a major business site and a security exhibition to be particularly security conscious, so the level of vulnerability at both of these sites is surprising," said Alexander Gostev, senior virus analyst at Kaspersky Lab.
"Canary Wharf is home to multinational banks and insurance companies and would be the perfect location for a hacker wanting to steal lucrative confidential or proprietary information."
Gostev warned that the fallout from an attack on these organisations could be catastrophic.
Kaspersky explained said it did not attempt to connect to the networks it found, nor to intercept or decrypt traffic.
The research showed that problems still exist for wireless technology. " Wireless networks and protocols have not got over their teething troubles, and can pose a serious risk in the hands of inexperienced users," the report concluded.
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