John Carrington worked in the Post Office when it was a state-owned monopoly on first the postal side and then the telecommunications side. He was appointed as the founding managing director of Cellnet, BT’s mobile telecoms arm, in 1983. He helped European partners to develop the GSM standard which became and world de-facto standard. He moved to run BT’s US operations. He then had a variety of jobs in telecommunication including working for Cable and Wireless.