Mr Caudwell says he cannot devote enough time to the business

Billionaire John Caudwell said he had taken the step after receiving "many offers" for all or part of the business from prospective buyers.

The decision followed a strategic review of the whole of Caudwell Group.

Mr Caudwell, who is ranked 29th in the Sunday Times Rich List, set up the business with his brother in 1987. Its annual sales now exceed �2bn ($3.5bn).

As a result of the decision to put the entire business up for sale, the group said it had delayed any final decision on the sale of its fixed-line Caudwell Communications business which it put on the market last month.

'Favourable comparisons'

Mr Caudwell told BBC News he had "no wish" to split the firm up and sell it as individual companies.

I strongly believe the group has enormous potential for further growth in the UK and internationally John Caudwell

He also refused to put a price on the business, but did add that it compared favourably with rival Carphone Warehouse.

Carphone - Europe's largest independent mobile phone retailer - is worth an estimated �1.9bn.

Carphone Warehouse Group itself has said it is interested in Caudwell's residential landline phone business Homecall.

Other brands under the Caudwell umbrella include 20:20 Logistics, the world's largest distributor of mobile handsets; mobile accessories distributor Dextra Solutions; the Mobile Phone Repair Company, and business insurance group Lifestyle Services.

High hopes

"I strongly believe the group has enormous potential for further growth in the UK and internationally ," Mr Caudwell said in a statement.

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

The 53-year-old, who owns 85% of Caudwell Group, originally set up the company 18 years ago in Stoke-on-Trent after discovering he could receive a discount on the usual �1,500 price tag of a mobile phone if he became a dealer.

The firm, then called Midland Mobile Phones, took eight months to sell its first order of 26 phones.

It now sells 26 phones a minute, has 350 stores across the UK and employs more than 8,000 people across the globe.

However, despite the planned sale Mr Caudwell has no plans to drop out of the business world, saying that "without doubt" he planned to set up another business after a "bit of a breather".