Radio 2 has surged to its biggest-ever audience as sister station Radio 1's breakfast DJ Nick Grimshaw lost more than a million of his older listeners since taking over from Chris Moyles.
Radio 2, which was named UK station of the year at the Radio Academy awards this week, attracted 15.6 million listeners in the first quarter of this year, according to Rajar audience figures published on Thursday.
It was a new high for the station, which has transformed itself over the last decade and a half, with record ratings for Chris Evans, Ken Bruce, Steve Wright and Graham Norton.
Radio 1, which is undergoing its own reinvention as it seeks a younger audience, had 10.5 million listeners, down 400,000 on the previous quarter but up 2.6% year on year.
Grimshaw had 5.85 million listeners, down from 6.3 million the previous quarter and his predecessor Moyles's final audience of 6.7 million.
But with the station under pressure from the BBC Trust and its commercial rivals to do more to appeal to younger listeners, the presenter was in the unusual position of being praised by his controller for losing listeners.
Radio 1 said the show had gained 130,000 listeners aged 24 and under and shed more than half a million over-25s during the three-month period.
Since taking over from Moyles in September 2012, Grimshaw has lost a total of 1.1 million listeners aged 25 and older, and gained 230,000 under-24s.
The Radio 1 controller, Ben Cooper, said: "I was asked to build a younger audience for Radio 1 and regenerate the brand, and these figures show we're doing exactly that.
"Grimmy and the breakfast show continue to gain young listeners … which is the challenge I set him."
Former late night DJ Grimshaw's switch to breakfast in place of the longstanding Moyles was a key part of Radio 1's new look and lineup, which also included Greg James's switch to drivetime in place of Scott Mills.
The revolution continued under Moir's successor Lesley Douglas and incumbent Bob Shennan, with a schedule of presenters that now includes Jeremy Vine, Simon Mayo, Mark Radcliffe and breakfast presenter Evans, who succeeded Sir Terry Wogan.
Radio 2's audience is now more than 50% up on the 9.9 million listeners it had at the end of 1999, when it was still more than 2 million listeners behind Radio 1, which 15 years ago had a weekly reach of more than 11 million.
Shennan singled out Evans, who attracted 9.83 million listeners in the first three months of this year, and Graham Norton, whose Saturday morning show drew 4.3 million listeners. Shennan said: "For a single show it is a phenomenal achievement."
Ken Bruce had a weekly reach of 8.4 million, with 8.1 million people tuning into Steve Wright's afternoon show.
Radio 4 and Radio 5 Live both lost listeners on the previous quarter, Radio 4 down 2.2% to 10.9 million while 5 Live slipped 1.8% to 6.2 million. Radio 4's Today programme had 7.06 million listeners.
Radio 3 was up on the previous quarter, but down year on year to 2.1 million.
Among the BBC's digital-only stations, the Asian Network took a tumble, down 28% on the previous quarter and nearly 14% year on year to 478,000.
Radio 1Xtra showed the biggest year-on-year gain, up just over 10% to 1.1 million, while Radio 6 Music, although down 1.8% on the previous quarter, was up 6.3% year on year to 1.9 million. Radio 4 Extra had nearly 1.7 million listeners.
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