In the
United Kingdom, the roll-out of
digital radio is proceeding since engineering test transmissions were started by the
BBC in 1990 followed by a public launch in September 1995. The UK currently has the world's biggest
digital radio network, with 103 transmitters, two national
DAB ensembles and 48 local and regional DAB ensembles broadcasting over 250 commercial and 34 BBC
radio stations across the UK. In the
capital,
London there are already more than 64 different digital stations available. In addition to DAB, radio stations are also broadcast on
digital television platform as well as
internet radio in the UK. Between April 2007 and April 2008 the BBC trialled
Digital Radio Mondiale on
mediumwave and
shortwave frequencies. Digital radio ensemble operators and stations need a broadcasting licence from the UK's media regulator
Ofcom to broadcast.