When Ceefax launched, it was rumoured that there were only four teletext-capable TV sets in the whole UK - one in the BBC director general's office, one for the director of engineering, one at Kingswood Warren and one in Colin McIntyre's home.

BBC: Ceefax: The early days

As viewers got a small taste of what Ceefax had to offer, millions of Britons during the 1980s invested in new teletext-enabled TV sets which gave them access to the full Ceefax service, which by now included recipe details for dishes prepared on BBC cookery shows, share prices, music reviews and an annual advent calendar.

BBC: Ceefax service closes down after 38 years on

Digital TV offers a wider range of channels than analogue TV and much of the content available on teletext-based services can be accessed on digital sets.

BBC: Digital Switchover

The technology for the world's first teletext service was developed by BBC engineers who were trying to find ways of providing subtitles on TV programmes for the deaf, rather than produce a news service.

BBC: Ceefax founding editor Colin McIntyre dies at 85