Which Dragon's Den investor founded the British retail group Phones 4u?

John Caudwell founded the British retail group Phones 4u.

Caudwell and his brother Brian built a mobile-phone retail business that became Phones 4u, one of the most recognisable names in Britain's mobile market. The company sold mobile phones and contracts through shops and later became a major national retailer.

John Caudwell appeared as a guest Dragon on Dragon's Den rather than becoming a permanent member of the regular panel. His presence reflected the programme's practice of inviting successful entrepreneurs to assess pitches alongside the established investors.

Phones 4u is sometimes confused with Carphone Warehouse because both were prominent British mobile-phone retailers. They were separate businesses. Phones 4u entered administration in 2014 after major network providers withdrew from its distribution arrangements, ending its high-street operation.