Employers should get used to the age of Facebook and other internet social networks and allow staff to electronically “poke” friends, announce what they are doing that day and join “just for fun” interest groups while at work, the TUC said yesterday.

The union group said that employees should not be able to use the sites without guidance and gave warning that workers who posted items online without thinking risked damaging their reputations and those of their employers.

The TUC called on businesses to set out guidelines for the use of Facebook, other networking sites and social e-mail rather than impose blanket bans. Several big companies have blocked access to the sites, concerned that their staff spend too much time reading news feeds about friends and taking part in other forms of cyber-slacking such as online Scrabble.

Brendan Barber, general secretary of the TUC, said: “Simply cracking down on the use of new web tools like Facebook is not a sensible solution to a problem that is only going to get bigger. It’s unreasonable for employers to try to stop their staff from having a life outside work, just because they can’t get their heads around the technology.”

The TUC said that although it was wrong for employees to spend hours on Facebook, it was wrong for employers to think that workers could not arrange some of their outside life while still at work.

Britain’s biggest supermarket chain became the latest employer to ban Facebook by blocking access. Tesco said that access was allowed only if employees could make a case for using it for their work.

Katja Hall, CBI’s head of employee relations, said: “The CBI’s advice to companies is that they should have a policy on staff use of the internet during work time, whatever the website.

“It is then down to individual employers how they tackle the increasing use of popular social networking sites . . . Employers do not want to police the private lives of staff or monitor private conversations.”

Rebecca Clake, research adviser at the Chartered Institute of Personnel and Development, said that there were lots of ways that people wasted time at work and that Facebook was just one website.

She said: “It is important not to get carried away with what people are doing every minute of the day. Chatting with colleagues at the water cooler can waste more time than a few minutes on the web.”

Lawyers backed the TUC’s call for guidelines and gave warning that failure to do so exposed businesses to legal claims.

One in five employers admits using such sites to check on a potential new worker’s employability; and in July this year the University of Oxford disciplined several students for breaches of its code of conduct, using pictures from Facebook as evidence.

Chris Boyle, head of employment at Napthens Solicitors, said: “This area is a minefield for employers and employees alike. Many people will put very private and personal information they would not want an employer to know on an internet site where it can be read by anyone.

“But for an employer to use this to make a decision on hiring and firing is not jut sensible and raises many legal issues, not least of which is privacy.”

He said that it made sense for businesses to have in place strict policies banning the use of such sites at work. “Good policies regarding the use of e-mails and monitoring of internet usage is a must for businesses who wish to take a robust approach.”

Allen & Overy, a law firm in the City, was forced to make an embarrassing U-turn on its Facebook ban earlier this year after a barrage of staff complaints.

The firm, which hires more than 100 graduate trainees in London each year, claimed that it had decided to reinstate access for Facebook because the site had a potential for “business networking”.

But insiders said that the firm was pushed into reversing the ban after complaints that staff were being prevented from keeping in touch with friends and making social arrangements.

Explore Career

• Graduate

• Senior Executive

• Recruiter Forum

• Top 50 Women

• Best 100 Companies

• Careers in

Times Recommends

• Inspirational leadership
• How to get a new job
• The reluctant CEO