VHG is right.
According to the 2009 edition of Radio Listeners Guide, the Digital Radio Working Group, established in 2007 by the Secretary of State for Culture, Media and Sport, with the purpose of working out a timetable for the change from analogue radio to digital, originally gave a target date of 2020.
However, they recommended that the digital switchover should not start until 50% of radio listening devices were digital, so even the 2020 completion date seems optimistic