BBC Radio 4 Extra is a British digital radio station from the BBC, broadcasting archived repeats of comedy, drama and documentary programmes nationally, 24 hours a day. It is the sister station of BBC Radio 4 and the principal broadcaster of the BBC's spoken-word archive, and as a result the majority of its programming originates from that archive. It also broadcasts extended and companion programmes to those broadcast on Radio 4, and provides a "catch-up" service for certain programmes.

In the United Kingdom, the roll-out of digital radio has been proceeding since engineering test transmissions were started by the BBC in 1990 followed by a public launch in September 1995. The UK currently has one of the world's biggest digital radio networks, with about 500 transmitters, three national DAB ensembles, one regional DAB ensemble, 48 local DAB ensembles and an increasing number of small-scale DAB ensembles broadcasting over 250 commercial and 34 BBC radio stations across the UK. In London there are already more than 100 different digital stations available. In addition to DAB and DAB+, radio stations are also broadcast on digital television platform as well as internet radio in the UK. Digital radio ensemble operators and stations need a broadcasting licence from the UK's media regulator Ofcom to broadcast.