A councillor thought he was on mute during a virtual meeting when he said "f***ing swallow that, you f*****s".
Dorian Phillips left his colleagues on Carmarthenshire Council in shock after the expletive-laden outburst in the middle of a training seminar.
It came immediately after a council officer explained that 95% of the south-west Wales local authority's decisions are made by the Cabinet.
Cllr Phillips, a member of Welsh nationalist party Plaid Cymru, which runs the council alongside the Independents - said this wasn’t the case, reports WalesOnline.
He claimed his comment was made during a business call he took during the seminar.
The Cabinet has no Labour representation, though members of the party were present at the meeting.
Newly-elected Labour councillor Shelly Godfrey-Coles asked Cllr Phillips to apologise at the time.
Fellow Labour Cllr Rob James has now called on Plaid to suspend Cllr Phillips and ensure he makes a full apology.
“This is truly appalling behaviour from an elected councillor and has really upset a number of councillors in attendance,” said Cllr James.
Alleging the language was directed at opposition councillors, Cllr James said it flew in the face of comments made by the new council leader, Plaid councillor Darren Price, of wanting to work with political opponents.
Cllr Phillips, who has represented Llanboidy since 2017, said: “I cannot deny that I used profane language but it was not directed to anyone at the meeting.”
He said he was viewing the seminar on Zoom in his business office and that during the course of it he’d had to deal with a business call “which became very heated [and] in which colourful language was used”.
He added: “I was horrified to learn that my microphone was turned on and the impression given that I was addressing the meeting.
"That was certainly not the case and I had no reason to do so.”
Cllr Phillips said on being told what had happened he immediately spoke to the council’s monitoring officer and, on their advice, referred himself to the ombudsman – a move also undertaken by Labour.
He said: “I deeply regret that this happened and I’m dismayed it should be seen as being directed at fellow councillors.”
Cllr Phillips added that all councillors who knew him knew he behaved with “complete respect” to all elected members.
