Ceefax is the BBC

BBC

The British Broadcasting Corporation is a British public service broadcaster. Its headquarters is at Broadcasting House in the City of Westminster, London. It is the largest broadcaster in the world, with about 23,000 staff...

's teletext

Teletext

Teletext is a television information retrieval service developed in the United Kingdom in the early 1970s. It offers a range of text-based information, typically including national, international and sporting news, weather and TV schedules...

 information service transmitted via the analogue signal, started in 1974 and will run until April 2012 for Pages from Ceefax, while the actual interactive service will run until 24 October 2012, in-line with the digital switchover.
During the late 60s, engineer Geoff Larkby and technician Barry Pyatt were working at the Designs Department (Television Group) of the BBC on a text transmission system.