Philips 9140 'remote control' mobile phone, designed for use with System 4, made by Philips, 1982-1987.
Before the first cellular mobile networks launched in Britain in 1985, British Telecom (BT) operated radiophone networks. These used similar technology to later mobile phones, but because they did not use a cellular system the numbers of users were very limited. System 4 was the last radiophone system BT operated. It was oversubscribed, which was one of the main drivers for introducing cellular mobile phone networks.