Broadcaster Stephen Nolan has apologised publicly for revealing his personal religious views on air.
Nolan revealed he was an atheist after being accused by a caller of bias against Christians.
He was involved in a debate about whether the new Causeway Coast and Glens Borough Council should retain a traditional prayer before opening for business.
The council voted to retain the traditional mayor's prayer from the old Coleraine Borough Council and add the Lord's Prayer.
A caller named as 'Stephen from Dungannon' told Nolan that on Easter Monday, he had said, "I don't believe in God" during an interview with Tyrone missionary Maud Kells.
The caller said: "That jeopardises your ability to chair this neutrally," adding, "I see the BBC as biased.
"I am a Christian myself. Every other day I see gay issues being raised and I take offence at you chairing this debate when you are meant to be neutral and you openly said that you do not believe in God.
"That jeopardises every discussion you have around these issues."
The presenter replied: "It was a mistake. I was trying to be honest. I was trying to have a discussion about God because it has been on my mind for a while. And it was a mistake. So I shouldn't have done it. And I appreciate that."
The caller replied: "There are not too many Christians among high-profile presenters on BBC.
"They are all openly atheist and they mock and they joke about the Bible and God and it seems to be that the Christian is the only one that can't express their view or else they get persecuted or pursued through the courts."
The presenter vowed to "fight" to give people of all views a voice.
BBC guidelines on impartiality say presenters "may not express personal views in BBC output".