GAA pundit Joe Brolly has initiated legal action against RTÉ, it has emerged.
Proceedings in the High Court on behalf of Mr Brolly were issued on Thursday.
RTÉ said on Friday that it did not comment on legal matters.
Mr Brolly, who is also a Sunday Independent columnist, worked with RTÉ on The Sunday Game until 2019.
Last March, Mr Brolly was disconnected during an RTÉ discussion on a united Ireland after the former Derry footballer and barrister made allegations against the Democratic Unionist Party (DUP).
Mr Brolly was responding to comments by DUP MP Gregory Campbell who told RTÉ's Claire Byrne Live show that a united Ireland "isn't going to happen" and claimed people involved in the debate "just don't get it".
“We are British,” said Mr Campbell. “Those three words, we are British. There’s nothing you can say, nothing you can do which will change that.”
In his response later in the programme, Mr Brolly said over video link the DUP was relying on short-term solutions to solve Northern Irish problems and accused the party of “laughing at the Irish language, laughing at Gaelic sports, the homophobia, the racism”.
Interrupted by Byrne who said Mr Campbell “might deny some of those charges”, Mr Brolly asked “which ones will he deny?” and attempted listing the accusations again. Byrne again interrupted, saying she was bring the conversation back to the studio.
Byrne later told viewers that she had “great respect for her guest” but that the programme “simply can’t stand over somebody name calling another person who isn’t here to defend themselves”.
Mr Brolly tweeted after the show: “I was taken off air and told it was because RTÉ could not risk me saying the DUP were homophobic, racist or sectarian. I must apologise to the DUP at once”. He attached screenshots to the tweet, and a number of subsequent tweets, which accused DUP members of using racist and homophobic rhetoric.