Companies that limit employee use of the internet are more likely to block travel and social networking sites than porn sites, according to a report released today at Infosec Europe 2008.

A survey of 300 UK companies found that travel and social networking topped the league of blocked sites, with personal webmail not far behind.

But the companies seemed less quick to filter gambling and pornography sites.

"Gambling and adult sites are the most obvious genres to be banned in the workplace," said Neil Hammerton, European vice president at Webroot, which commissioned the research

"They are also the most socially stigmatised, and it seems that these areas are now relatively self-policing.

"However, it seems that travel and webmail are up there with social networking in terms of drains on time at work.

"These sites are clearly less stigmatised in the workplace which appears to indicate why they have overtaken the obvious choices in terms of which are the most frequently blocked."

The survey found that it is not just time-wasting that is behind the blocking. Over half of the firms questioned felt that visiting social networking sites can compromise security.

Results from the biannual IT security survey from the Department of Business Enterprise and Regulatory reform released today found that 38 per cent of UK businesses block some sites from their employees.

This rises to over 80 per cent for larger firms. Under half of firms log web histories, compared to 86 per cent of large companies.