Phones 4u chief executive John Caudwell - who apparently does not use e-mail himself - says the e-mail ban is saving his staff an average of three hours a day, equating to savings of �1m a month.

"I saw that e-mail was insidiously invading Phones 4u so I banned it immediately," said Mr Caudwell.

"Management and staff at HQ and in stores were beginning to show signs of being constrained by the e-mail proliferation," he observed.

Staff are instead being told to speak to each other in person or pick up the phone.

There are, of course, some exceptions, including communicating with customers abroad.

Turnaround

Mr Caudwell claims the ban on internal emails has turned his business around.

"The ban brought an instant, dramatic and positive effect," Mr Caudwell said.

"The quality and efficiency of communication have been increased tremendously in one fell swoop - things are getting better and people aren't tied to their PCs," he said.

The statement did not mention whether text messages were still allowed.

Mr Caudwell, Britain's 26th richest man with a personal fortune of �840m, has hit the headlines with a number of unusual employment tactics, including running a competition with a �100,000 job as the prize.