Businesses in the City are failing to take basic precautions to secure wireless networks, despite the high-profile threat of drive-by hacking.

The second annual Wireless Security Survey of London shows an increase in wireless local area networks (Lans), but previous security warnings have not been heeded.

The survey, conducted by risk management specialist Y/Zen on behalf of RSA Security, discovered 328 wireless access points in the City, a big increase on the 124 identified in the previous study.

A third had insufficient levels of security, leaving corporate data vulnerable to attack.

Tim Pickard, European strategic marketing director at RSA, explained that users can address the problem easily.

"Only a third of the access points were using Wired Equivalent Privacy [a wireless Lan security standard], and that's exactly the same number as a year ago," he said.

"The findings also show that 120 of the access points have default settings that reduce security, and 100 organisations had named their networks in a way that is easily identifiable.

"This isn't a technology that cannot be made secure. It comes down to a lack of education."

Many new laptops and PDAs, for example, are sold with wireless cards which are switched on as part of the default settings, and users may often be oblivious to the potential threat.

"Organisations need to be aware that wireless Lans are probably active in their organisation, even if they don't realise it," said Pickard.

Phil Cracknell, security specialist and Y/Zen associate, pointed out that users must secure wireless Lans to the same level as wired networks.

"There is so much publicity about this subject, that it's difficult to understand why companies are still ignoring the warnings," he said.

"There's no reason for this to happen. It's a standard security policy fix that anybody can do."