Taking a 10-minute online break during the working day helps to reduce stress and can sharpen the mind, according to research published by PopCap Games.

Companies that frown on such activity could be contributing to a loss to UK Plc of up to £4bn every year, the casual games firm claimed.

PopCap reached this formidable figure by multiplying the recorded productivity increase identified in its PopCap Break Report 2008 by the 2008 UK turnover figures for services and highly skilled jobs.

Recent research conducted by employment law firm Peninsula found that seven out of 10 companies now ban access to social networking sites, and are considering banning personal internet access altogether.

However, PopCap's study suggests that taking a 10-minute online break benefits the employee and the company as a whole.

Far from distracting employees from their work, these "electronic breaks" actually increase staff efficiency and morale.

The findings are based on psychometric trials carried out on a cross section of UK businesses under the supervision of Dr Tomas Chamorro-Premuzic, a psychologist at Goldsmiths University.

The trials suggest that spending 10 minutes on activities such as puzzles, casual games, social networking, personal email, online shopping and general " life admin" can have a positive impact on productivity.

"Work days are becoming longer, workloads are becoming more demanding, and UK bosses are introducing internet bans to help combat alleged productivity losses and inappropriate use of workplace resources," said Dr Chamorro-Premuzic.

"Yet bosses are missing a trick by introducing e-bans. Allowing workers more freedom at the PC can benefit morale and boost company profits.

"In addition to allowing their mind to switch off from their work worries, employers can foster a more trusting and enjoyable environment."