An Apple iPod music and video player is shown in an October 2006 image.

Nearly a quarter of British workers plug in their MP3 players to listen to music while on the job -- sparking lively debate over whether they should be banned, a study said.

Over 30 percent of companies have outlawed using devices like the ubiquitous iPod in the workplace, according to Woods Bagot, an international design practice.

"By wearing the highly-visible, white headphones, they're ... sending a signal to colleagues that they don't want to be bothered," said Simon Pole, head of the company's head of corporate interiors.

According to the study, 22 percent of workers spend an average of three hours per day listening to MP3 players.

But some argue that the trend is only natural: previously workers were physically separated by walls, whereas offices are increasingly open-plan nowadays, pushing them to erect new barriers.

"The MP3 player is the simplest way to create your own office," said the company.

And Cary Cooper, professor of organization psychology at Lancaster University, and author of "Shut up and Listen: The Truth About How to Communicate at Work," said bans were counter-productive.

"Employers are wrong to ban MP3 players from the workplace. It's crucial to give workers autonomy, and bans of any sort can alienate workers," he said.

"Bosses shouldn't care about how employees accomplish their objectives or if they want to engross themselves in MP3 players -- as long as the job gets done," he added.