London, Oct 26 (PTI) In today's world, popular social networking sites like Twitter and Facebook are without a doubt the best way to stay connected with friends and share what is happening right now.

But, a new survey has revealed that the popular sites are actually costing British businesses 1.38 billion pounds a year in wasted time.

In fact, according to the survey, more than half of office workers use the social networking sites like Twitter and Facebook for personal use during the working day, and admit wasting an average of 40 minutes a week each.

One in three of the 1,460 office workers surveyed also said they had seen sensitive company information posted on social networking sites, leading to fears about how workers use the Internet, 'The Daily Telegraph' reported.