In the mid 1970s, it was the radiopager that marked out the busy professional on the move.
Radiopagers were a stepping stone to mobile communications - call alerts and short messages could reach you if you were in range of a radio transmitter - but you still needed to find a telephone to return the call.
Surveys carried out by the Post Office in 1968 showed that Britain was ready for wide area radio paging. The first system was introduced in 1973, covering the Thames Valley. It was extended to London in 1976. By the end of the 1970s, most of Britain was covered by several networks.
The reign of the pager as the primary form of mobile communications lasted into the early 1990s. By then, mobile phones had made the pager almost obsolete.