Hundreds of bosses are expected to block staff from accessing the Channel Four Big Brother Web site when it launches on Friday, following the massive dip in productivity that British companies suffered last year when hundreds of employees took advantage of the live footage on their corporate machines. Web filtering companies are warning big businesses that employees logging onto the live video streams for an hour each day could cost them up to £250,000 for that period, amounting to £6m in a year. If employees become addicted to the second instalment of the voyeuristic experiment in the same way that they did last summer, corporate networks could be jammed by a shortage of bandwidth, preventing work-related emails from getting through. "Big Brother will be highlighting a problem that already exists," said Martino Corbelli, marketing manager for SurfControl, which produces software to restrict Web surfing. "The issue isn't about companies clamping down on staff Internet use -- it's just another resource that companies need to manage and have some control of, if they wish to avoid legal and productivity problems." Last year more than 700,000 people visited the Big Brother site at least once in July, with the average user tuning into the Web cams for average sessions of 25.3 minutes. This year the video streaming promises to be instant, enabling users to see the action at the same time as the production crew. "A lot of people were unable to get video-streams last year due to the way in which Internet broadcasting works, but this year we will be taking the streaming to the edge," said Morgan Holt, editor of the Big Brother Web site. Bosses have become increasingly confused on the issue of monitoring staff Internet usage, with many companies failing to have an Internet policy in place. Whilst the Regulation of Investigatory Powers Act (RIPA) endorses the unrestricted monitoring of emails by employers, companies will be breaking the law by doing so if they don't have a written policy in place. "It's a legal minefield at the moment -- RIPA and the Human Rights Act have only confused the issue of staff monitoring," said Corbelli. SurfControl software enables employers to impose restrictions on thousands of URLs in 39 different categories. "It may not be appropriate for bosses to block the entire Big Brother Web site, but just the part that is offering the streaming," said Corbelli. He argues it is important to allow employees some freedom on the Web, without the company becoming a victim of an over-liberal environment. For complete business coverage, see ZDNet UK's Enterprise Channel. Have your say instantly, and see what others have said. Click on the TalkBack button and go to the ZDNet news forum. Let the editors know what you think in the Mailroom. And read other letters.