John Caudwell, the mobile phones billionaire, today formally put his communications empire, which includes the high street retailing phenomenon Phones4U, up for sale.

With predicted pre-tax earnings before depreciation of more than £115 million this year, Mr Caudwell's group, which he co-founded 17 years ago, is likely to rival the listed Carphone Warehouse in terms of value and could fetch comfortably more than £1 billion if the sale goes through successfully.

Mr Caudwell, who at 29th in the Sunday Times Rich List with a fortune of £1.28 billion is one of the nation's wealthiest men, owns 85 per cent of the Caudwell Group businesses, which he set up with his brother Brian in Stoke-on-Trent in 1987.

Brian Caudwell owns 10 per cent of the Caudwell Group and the company's finance director owns the remaining 5 per cent.

Mr Caudwell, who before setting up Caudwell Group ran a car repair business, said he decided to sell the group after bringing in bankers at Rothschild, the independent investment bank, to carry out a strategic review.

Rothschilds will manage the sale process.

After joining the rapidly expanding mobiles sector as a dealer, Mr Caudwell developed his group into a diverse international business that today employs 8,500 people, boasts turnover of more than £2 billion and runs a fixed line operation as well as repairs and an equipment supplier.

Phones4U operates out of 350 stores in the UK and is busy investing ahead of the crunch Christmas trading period.

"I strongly believe the group has enormous potential for further growth in the UK and internationally, led by the proven, autonomous and entrepreneurial management teams built up over a number of years," Mr Caudwell said today.

"The hands-on contribution required from me as the principal shareholder is, therefore, now more limited and I have, as a result, decided to invite offers for the group," he said.

The move to sell the group as a whole effectively puts on hold Mr Caudwell's proposed sale of Caudwell Communications, the fixed line telephony unit that was made available in September.

Mr Caudwell has already received "many approaches from buyers interested in acquiring all or part of the group". These include potential private equity buyers, as well as interested parties in the trade sector.

Mr Caudwell has said that, ideally, he would like to sell the group as a whole, rather than breaking it up and selling off the parts.

Carphone Warehouse has made no secret of its interest in buying Caudwell Communications in the past, and may now be in the running to bag the entire group.

Carphone's shares slipped more than 2 per cent to 211.75p in an easing wider market this afternoon.

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