BBC Radio 4 boss Gwyneth Williams is leaving the corporation after eight years in the role.
Williams was appointed Controller of Radio 4 in September 2010 after numerous roles at the BBC, including the head of radio current affairs and director of BBC World Service English.
During her tenure at Radio 4, she has seen the station reach record listener numbers, with a peak of 11.5 million tuning in in the months after the EU Referendum and the 2017 General Election.
Williams, who joined the BBC in 1976 as a trainee talks writer, has also seen digital station Radio 4 Extra double its audience to more than two million.
She said: “I have had eight wonderful years running Radio 4, a national treasure at the very heart of the BBC’s public service purpose.
“My goal has been to keep the station intelligent and to build audiences by smartening up not dumbing down, making sure Radio 4 is the place to come for greater understanding, particularly in these turbulent times.
“I have worked with remarkable people throughout my career and none more so than my tiny, hard-working and brilliant team at Radio 4.
“I grew up listening to the World Service in apartheid South Africa, so that too has a special place in my heart.”
Williams introduced programmes including The Life Scientific with Jim Al-Khalili, Only Artists and Soul Music, putting an emphasis on both science and culture, during her time as Radio 4 Controller.
She has also been praised by the BBC for introducing a “wider range of voices” to the station, putting more women at the helm of news programmes and for having diverse presenters across a number of titles.
Tony Hall, the corporation’s Director-General, said: “It’s hard to overstate Gwyneth’s contribution to the BBC and our audiences – few can match her achievements.
“From her time in current affairs, the World Service, and Radio 4, Gwyneth has always put giving listeners the best in thoughtful and illuminating programming first.
“She’s been a dear colleague and I’m personally thankful to her for all she’s done. Whilst she’ll be very much missed, I wish her all the best for the future.”
Bob Shennan, director of radio and music, said Williams has “been a great custodian and under her watch over the last eight years the station has found new ways to broaden our understanding of the world through its rich mix of news, documentaries, drama and comedy.”
Williams will continue as Radio 4’s Controller until late spring.
Her replacement will be appointed in due course, the BBC said.