Butters joined BBC Radio 1 early in 2003

Butters will leave in February to be replaced by DJ duo JK & Joel, who only joined the station in the summer from Manchester's Key 103.

The changes also see former breakfast show host Sara Cox return to Radio 1 on Saturday and Sunday afternoons.

Scott Mills stays with the drivetime slot he has presented since Cox went on maternity leave earlier this year.

Cox moved from breakfast to drivetime before taking time off to give birth to daughter Lola Anne, who was born in June.

Sara Cox took time off to have her first child

But the show is now longer than it was before she left, and Cox said she wanted to be back home in the evenings to put her daughter to bed.

"I'm looking forward to being back, I've really missed being on the radio," she said.

"I'm going to do my best not to burst into nursery rhymes, although The Wheels On The Bus is an old-school classic."

Countdown

Chart presenter Butters, who joined the station in February 2003 from Newcastle-based Galaxy 105, is not having his contract renewed.

JK & Joel joined BBC Radio 1 this summer

JK & Joel - Jason King and Joel Hogg - will feature download and album charts in their new show, as well as the traditional singles countdown.

Radio 1's chart show has come under pressure from rival stations over recent months.

National chart show Hit 40 UK recently recruited Katy Hill and Simon Hirst to front its Sunday rundown, while former Radio 1 presenter Mark Goodier hosts a rival countdown, the Smash Hits Chart.

Head of mainstream programming Ben Cooper said: "It's going to be great to have Sara back, and it gives JK & Joel a chance to breathe new life into what remains the biggest single show on the station.