Three SDLP councillors in Belfast have dramatically quit the party, accusing Colum Eastwood of a lack of leadership.
Former Lord Mayor Pat Convery and councillors Declan Boyle and Kate Mullan said they had been "treated with disrespect by the party we have served for decades".
Their resignations almost halve the SDLP's already depleted City Hall team, leaving just four councillors on its benches - only one more than the Progressive Unionist Party.
While their departure won't endanger Mr Eastwood's leadership, it is a huge blow to the party coming just 10 days after its three MPs lost their Westminster seats.
The trio was suspended by party headquarters in April after abstaining from a council vote condemning the harassment of women by anti-abortion activists outside reproductive healthcare facilities. All the other councillors in the meeting, including those from the DUP, voted in favour of the resolution.
The SDLP leadership had instructed its City Hall group to support the motion, which its other four councillors did.
Last night the party said party procedure had been followed, but the councillors had "decided not to participate in that process".
The three who abstained told the Belfast Telegraph that they were quitting the party with "profoundly heavy hearts".
They said they would not resign their seats but would continue to sit on the council as "independents". They stated that they had "no current plans" to join another party.
Mr Convery, a former SDLP vice-chairman who was first elected to Belfast City Council 16 years ago for the Castle ward, said: "I never thought it would come to this. I've been SDLP all my life, my family are SDLP.
"The party I joined was one of inclusiveness and I feel that no longer applies.
"The SDLP needs to go back to its roots of being a broad church where everyone is welcome."
The councillor said that "moral issues should be matters of personal conscience and party policy should reflect that".
Mr Boyle claimed that their request for a meeting with Mr Eastwood had not been granted.
"We have been treated very shabbily. Between us, we have over 50 years' SDLP membership," he said.
"Whether people agree or don't agree with how we voted, I reckon most would think we at least deserved a meeting with the leader to discuss the issue.
"For that not to happen, for Colum Eastwood not to meet us, is a poor show.
"We have seen a total lack of leadership. There is much more to running a party than performing well in TV debates."
Ms Mullan said: "It is a very sad day for me to be leaving the SDLP but it is impossible to remain in a party that has treated me this badly. It should never have reached this stage."
She said that the trio had held back from resigning before the Westminster election so as not to damage the party's chances.
"We purposely didn't make a fuss about any of this or resign before polling day," she added.
"We did the honourable thing and hung on. We hoped that the matter would be resolved to everybody's satisfaction after the election but that hasn't happened.
"It's now two-and-a-half months since we were suspended and we can't carry on in limbo any more. It's embarrassing when you're trying to help constituents and they ask if you're still suspended."
Mr Boyle said that the suspensions meant that he and councillor Mullan had been unable to canvass for Alasdair McDonnell in the Westminster election.
"Kate and I both represent areas in South Belfast where it was a do-or-die battle against the DUP," he said. "At a time when all hands were required on deck, Alasdair was deprived of two local councillors on the campaign trail.
"I put up 1,000 posters but I couldn't knock doors in my own street to ask people to vote for him because it would have been embarrassing and harmed the party had voters raised my suspension."
The motion before the council on April 3 was proposed by Green councillor Georgina Milne, who said she had been contacted by sexual health clinics concerned that people entering their premises were being forced to "run a gauntlet of intimidation and harassment".
Ms Milne and the PUP's Julie-Anne Corr-Johnston, who seconded the motion, said any councillor's position on a woman's right to choose was irrelevant because the issue was about protecting people from intimidation.
The three councillors told the Belfast Telegraph that they "totally opposed the harassment and intimidation of women" and abstained from the vote "as the SDLP are a pro-life party".
Four days after the vote, councillors Convery, Boyle and Mullan received a letter from SDLP chief whip, South Down MLA Colin McGrath, informing them of their suspension.
"Your vote has brought considerable disrepute to the party in all forms of print, broadcast and social media and was contrary to party policy and to the direction sought and provided from the party on the day," it said.
Explaining that the whip would be withdrawn from them "for a period", Mr McGrath continued: "It is with regret that I have had to take this action as your record has been hitherto exemplary. It is the party leadership's intention to discuss this matter with you in due course. I am happy to discuss any element of this disciplinary action."
Mr Boyle said that it was wrong for disciplinary action to be taken against the trio before the party hierarchy met them.
"We weren't given the chance to make our case at a meeting. We were sentenced in advance of that in a draconian approach," he said.
The councillors were told a disciplinary panel would be set up, but wrangling over whether a meeting with the party leadership should happen first meant it never occurred.
The trio's solicitor Joe Rice said: "The SDLP leadership showed no respect for three experienced and distinguished councillors and no appetite to resolve issues which clearly affected the party's pro-life stance.
"The party's rules and mechanisms to deal with this disciplinary issue were at best vague and at worst deficient or non-existent."
In a statement, the SDLP said that following a breach of party discipline, the three councillors had the party whip withdrawn.
It added: "The party process has been followed to deal with the matter. The councillors decided not to participate in that process. We thank them for their service."
Kate Mullan was elected on to Belfast City Council in 2011. She represents the Lisnasharragh area of the city.
She has also worked in Alasdair McDonnell’s constituency office.
Pat Convery has represented the Castle area of north Belfast since June 2001. He served as Lord Mayor in 2010 and was SDLP group leader at the time of the vote in April.
Elected in 2014 in the Botanic ward, Declan Boyle was one of the party’s most high-profile councillors.
He is a landlord in the university area of south Belfast.