Former ACT opposition leader Leanne Castley has quit the Canberra Liberals and will sit on the crossbench, accusing her old party of allowing a toxic culture and saying she had been threatened with physical violence.
The Liberals' leader, Mark Parton, flatly rejected the party's culture was toxic and Adam Morris, the party's president, said he was shocked to hear the allegations of physical violence, bullying and harassment.
Ms Castley said she would sit on the crossbench for the rest of the term and had not had any conversations with other parties, such as One Nation, about switching allegiances.
"There is no one issue or reason for why I am going. I have simply had enough of being part of an organisation with such a toxic culture. There has been a long-running campaign against me of bullying, intimidation, lies and even the threat of physical violence," Ms Castley said.
"Conduct which is tolerated and accepted but should be condemned. The community and the many decent people in the Liberal Party all deserve better than they get. These things have taken a personal toll.
"But, more importantly, they have been a distraction. After the week that coercive control legislation was introduced I realised how much of my time and energy has been dragged into dealing with internal cultural issues. And I want my energy to be used for the things that matter."
Ms Castley said she would not go into the details of the alleged threat of physical violence, saying she did not want to litigate the issue in public.
"Look, what has gone on is extremely serious but it's within my remit to do whatever I want with those and, as I say, I'm not going blow for blow. I'm drawing a line in the sand and I'm moving forward today," she said.
Mr Parton said Ms Castley's resignation was disappointing but rejected the allegations of his party harbouring a toxic culture.
"It's a political party. It's a robust environment. There are people involved in this pursuit with very strong opinions who want to put those opinions forward but I'm not sure that translates to a toxic culture," Mr Parton told ABC radio.
Mr Morris, who is married to Deputy Opposition Leader Deborah Morris, said he was not aware of Ms Castley's allegation of a threat of violence before Tuesday morning and that the Liberals did not have a problem with toxic culture.
"I think it's really important, though, that we remember we're all human and politics can elicit sometimes a lot of excitement from the broad church, regardless of the colour, of politics," he said at an unusual joint press conference with Mr Parton.
"And we need to remember to treat each other like human beings. So, no, I don't [think the party has a problem with toxic culture], but certainly there's always challenges across the different political parties to ensure that we're relating to each other respectfully and honourably."
Mr Parton would not be drawn on when he became aware of Ms Castley's allegation of a physical threat or if he was present when the threat was made.
"I think we've made it clear that I'm not going to be making comments on specific matters today. Just with a view of privacy, confidentiality, and the fact that I'm just not making comments on those individual allegations," Mr Parton said.
Mr Parton said he had nothing to refer to the police and was confident he had acted appropriately under the Legislative Assembly members' code of conduct.
The code requires members to offer and provide support to people making complaints of bullying, sexual and other harassment, sexual assault or discrimination and seek expert advice and assistance as appropriate.
Mr Parton also said Ms Castley had not been expelled from shadow cabinet last week and "certainly wasn't told not to go to party room meetings".
Ms Castley stood by her view the party had a toxic culture when she addressed the media at the Legislative Assembly on Wednesday morning.
"Now does that mean I'm not able to handle a robust conversation? Absolutely not. I've had many of them and I think it's time that we allow people to speak for themselves and, as I say this, is my experience. It has been my experience," she said.
Ms Castley said there had been allegations levelled at her during her leadership of the party but "all of those allegations were dismissed and that information never got leaked to the media".
"It is a robust job that we have here and it's important to have good honest conversations rather than leaking and backbiting and undermining," she said.
"I have no time for that anymore and that's why I stepped away."
Mr Parton said he understood Ms Castley had endured a torrid time over the past 18 months.
"She's been in pain and, you know, much of that pain is justified. ... There's always going to be a swirling challenging of ideas and challenging of positions and sometimes that is a little bit robust," he said.
"But I just, I reject the allegations about the toxic culture of the party."
Ms Castley led the Canberra Liberals for just over a year until November 2025 and resigned after a period of party room tensions following her convention-defying decision to suspend her predecessor, Elizabeth Lee, and Peter Cain from the party room after the pair crossed the floor.
Ms Castley's leadership faced an earlier challenge when Mr Cain resigned from shadow cabinet in June 2025, declaring he could no longer support the then leadership team and he had a duty of care to staff "who deserve to work in a safe, supportive, and respectful environment".
On Wednesday, Ms Castley said the cultural issues in the party had contributed to her resignation from the leadership.
Asked whether she had some responsibility for the party's culture as a former leader, she said: "We worked really hard to turn the ship around, and I stood down because we worked really hard to bring that culture together and, as I say, I had hoped that it would change when I stepped down from the leadership but it just kept coming."
Ms Castley, who was first elected in 2020 to the northern ACT seat of Yerrabi, had also been critical of a potential power-sharing deal discussed by the Liberals and the ACT Greens, saying in February the Liberals needed to stay true to their values.
"I believe you cannot expect two parties to effectively govern together when their core principles are incompatible," she said at the time, in remarks seen as breaking with shadow cabinet solidarity.
Ms Castley's resignation from the Liberals means the party would no longer have the numbers to oust Labor from office with the ACT Greens, whose ranks are expected to be bolstered by the return of Rebecca Vassarotti in a countback on Thursday to replace former leader Shane Rattenbury.
Ms Castley indicated she had considered whether quitting the Liberal party was a betrayal of the voters who had backed her as a Liberal candidate.
"But in the Hare-Clark system, people vote for me as a person and I'm so grateful the electorate did and that's the questions that I'll answer when I'm back out there, as I will be during the weekend," she said.
Ms Castley said whether she contested the next election would be up to the electorate, and it would be up to them to now embrace her as an independent.
Asked whether Ms Castley should resign from the Assembly after quitting the party she was elected as a candidate for, Mr Parton said no.
"Ultimately she's not the first to do that from either side of politics. And I'm sure she won't be the last," he said.
Ms Castley is the sixth former Liberal to move to the crossbench in the Legislative Assembly since self-government began in 1989. A Liberal-turned-independent has never successfully recontested their seat.
