Office workers who spend their working hours logged onto social networking sites like Facebook are causing UK employers to lose more than GBP130 million every single day in terms of lost productivity.

That is according to a new study from law firm Peninsula. Surveying 3,500 companies all over the country, it learned that 233 million hours of working time are lost to Facebook each month, costing companies a total of GBP30.8 billion a year.

"Why should employers allow their workers to waste two hours a day on Facebook when they are being paid to do a job?" asked Mike Huss, of Peninsula.

"Continued misuse of the internet by an employee is a situation when disciplining and sacking a worker is acceptable. Sites such as Facebook will only get more popular as time goes by and so I anticipate productivity will suffer as a consequence."

Following the news that several large companies including Lloyds TSB, Goldman Sachs and Transport for London have banned workers from using Facebook, the Trade Union Congress (TUC) called for employees to be given time to use social networking websites at work.

A recent poll of 600 employees from IT security firm Sophos revealed that 43 per cent were blocked from being able to access such sites at work.