Security of wireless networks in London has deteriorated over the past 12 months according to a report commissioned by RSA Security.
More than a third of London businesses with wireless Lans are open to the hacking of their corporate networks. Last year researchers found only 15% of wireless networks insecure.
Tim Pickard, RSA Security area vice-president of international marketing, said, "The research shows that corporate wireless networks in London are growing at an annual rate of 62% and 36% of these businesses remain unprotected from attack."
The survey revealed that many businesses had failed to take basic security precautions such as reconfiguring their default network settings.
In London, the research found that 26% of access points still had default settings. RSA warned that this means that wireless network access points were still broadcasting potentially valuable information, which could be sabotaged or used to launch subsequent attacks.
In addition to the business security issues, researchers also found an increase in public access wireless hotspots - 12% of all wireless network access points in London fell into this category.
The growth in public hotspots may compound the security problem enterprises are facing.
Phil Cracknell, chief technology officer at netSurity and author of the research, said, "The rapid rise of public access hotspots runs in parallel to the increased risk to businesses that operate wireless networks with little or no security.
"Accidental or intentional connection to a corporate network can bring with it a series of security issues including loss of confidential data and installation of malicious code. Fuelled by the availability and abundance of hotspots, mobile users now expect to find and know how to use a wireless network."