Which company did Dragon's Den investor John Caudwell found?

Dragon's Den investor John Caudwell founded Phones 4u.

Phones 4u was a British mobile-phone retailer established by Caudwell and his business partner Brian McGowan. The company grew during the rapid expansion of mobile-phone ownership in the United Kingdom, selling handsets and network contracts through a national retail operation. Caudwell later became known for philanthropy as well as for his business career.

John Caudwell joined Dragon's Den as an investor for a period, bringing experience from the telecommunications and retail sectors. That background made mobile technology, distribution and consumer sales natural areas of expertise when he assessed entrepreneurs' proposals.

Phones 4u is often confused with Carphone Warehouse because both were major British mobile-phone retailers. They were separate businesses founded by different entrepreneurs. Carphone Warehouse was associated with David Ross, Guy Johnson and Charles Dunstone, whereas Phones 4u was the company built by Caudwell and McGowan.