Mayor Livingstone, Facebook user

In a rising corporate tide against the site, Transport for London is the latest in a string of employers to ban Facebook access after growing concerns that its staff spends too much time on it.

Transport for London manages London's bus and Tube network, employing over 20,000 staff, some remotely, reports The Guardian.

comScore reports that UK users spend an average of three hours and 11 minutes on Facebook each month. The global average is three hours and 41 minutes. Recently, however, London outpaced Toronto as the Facebook capital in terms of users.

Facebook users include Ken Livingstone, the mayor of London and chairman of the TfL board.

According to the telegraph, 70 percent of UK employers have banned access to the site. Others have informed staff that use of Facebook during office hours can result in termination.

Meanwhile, companies like Germany's Siemens, which boasts 6,430 employees on Facebook, hope to integrate the community in corporate relations.

Siemens is developing an app that helps link the site with internal staff blogs.