Radio 1 controller Ben Cooper says this was "the right moment" for Chris Moyles to announce he is leaving the station's breakfast show.

The 38-year-old has hosted the show since 2004 and will be replaced by late-night DJ Nick Grimshaw from September.

Ben Cooper wouldn't give details about his discussions with Chris Moyles: "I always said when the moment came, it would be a conversation between me and Chris, and it was.

"That conversation will remain private."

Ben Cooper is under pressure to attract a younger audience to Radio 1.

He's young, he loves his music and he's got a great sense of humour Ben Cooper on Nick Grimshaw

"We have an average age of 32 and I've been asked by the BBC Trust to reduce it," he said.

"Today's decision is part of an overall strategy to try and make sure that average age does come down.

"You also look at the music we play, and what we talk about."

Radio 1 presenters Scott Mills and Greg James swapped shows in April, while DJs like Gemma Cairney, Danny Howard and Jameela Jamil were given regular slots.

The controller described Grimshaw as a fantastic broadcaster and said: "He's young, he loves his music and he's got a great sense of humour which comes across in his interviews."

'Dream come true'

Ben Cooper took over as controller of Radio 1 and its sister station BBC Radio 1Xtra last October.

He said at the time: "This is a dream come true and I'm honoured to be leading the BBC's youth music radio stations."

Ben Cooper began his career in BBC local radio, presenting and producing on Hereford & Worcester.

He was also a journalist at Three Counties Radio before becoming a producer at Radio 1.

After a spell at Capital Radio as an executive producer, he returned to Radio 1 first as head of mainstream then as head of programmes.

During that time he hired Nick Grimshaw, as well as Greg James, Fearne Cotton and Reggie Yates.

He also extended The Chris Moyles Show by half an hour.