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 outlawed¹ 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 corporate² 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: previously³ workers were physically⁴ separated by walls, whereas offices are increasingly open-plan nowadays, pushing them to erect⁵ new barriers.

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

And Cary Cooper, professor of organization psychology⁶ 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 alienate⁷ workers," he said.

"Bosses shouldn't care about how employees accomplish their objectives or if they want to engross⁸ themselves in MP3 players -- as long as the job gets done," he added.