But Speirs this morning did not rule out returning to the party’s top job one day, telling ABC Radio Adelaide that “I’m not closing the door on anything” even if a leadership return would “probably be unlikely”.

Speirs’s bombshell resignation on Thursday afternoon followed months of speculation about his leadership, which intensified after the party’s damaging loss in the Dunstan by-election in March.

His resignation will likely trigger a ballot for the leader and deputy leader positions at a joint-party room meeting on Monday, with moderate frontbenchers John Gardner, Josh Teague and Vincent Tarzia the most likely candidates.

Speirs remained confident today that he still had majority support from the party room – which in April 2022 elected him leader with 18 votes of a possible 24 – and the party’s rank and file membership.

“I was not pushed,” Speirs said today regarding his resignation.

“But one or two bad apples spoil the whole barrel.

“And at the end of the day, if I had declared the leadership vacant, I would probably have been the only candidate if I had been willing to stand.

“Even if there had been a challenge – and there was none forthcoming – I suspect I would have gotten a similar or greater vote than what I would have achieved in the 2022 ballot.

“I had put a lot of emphasis on making sure that I held the party in a unified way. That old history of the Liberal Party at war with itself, I didn’t want to be a part of that.”

Speirs said he wanted to “really clearly articulate who and what we stand for”, mentioning home ownership, individual freedom, standing for regional South Australia and small business as part of his policy vision.

“I was plotting all that out and then in this second half of the term start to release thoughtful, evidence-based policies,” he said.

“And we were on that track, but some people just couldn’t wait for that plan to unfold effectively, and undermined.”

Speirs’s resignation comes at a critical time for the Liberal Party just 18 months away from the March 2026 state election.

The party’s annual general meeting is scheduled for later this month where elections will be held for key positions on the party’s state executive.

The Electoral District Boundaries Commission will also on August 15 hand down its draft ruling on the electoral map for the next state election, a decision which could have a significant impact on the Liberal Party’s prospects in several key marginal seats and will effectively fire the starting gun on state-level preselections.

Speirs said he had done work on candidate recruitment and whoever the new party leader will need to “settle things down and move on quickly with these matters”.

“We need to get people preselected in key seats and things like that, and I had an indicative timeline in my head as to when that would happen,” he said.

“Hopefully all that can still continue.

“There can be, if the party gets its act together, there can be a level of continuity.”

After the Dunstan by-election loss in March and MacKillop MP Nick McBride’s defection last year, the Liberal Party only holds 14 seats compared to Labor’s 27 heading into the next election.

David Speirs with Nick McBride in August 2022, before McBride’s defection from the party a year later.

Asked about the next state election, Speirs said: “I think it’s going to be very difficult for the Liberal Party of South Australia.”

“Peter Malinauskas and Labor are a formidable operation, there’s no doubt about that.

“I think it will be a challenge now to attract candidates and, again, because I’d done a lot of work on that and I was pretty confident with the direction we were heading with some of our candidacies.

“The Liberal Party has got some serious soul searching to do now. But, I think in terms of articulating what and who we stand for, I’ve done quite well at leaving a foundation for the new leader to build on and I hope they can leverage good policy around that.

“It’ll have to come down to policy. The party will have to participate in the battle of ideas, they’ll have to get on with that really thoroughly and rapidly and get good ideas into the public domain to challenge Labor on.”

After speaking on radio this morning, Speirs did not take questions from media waiting outside, after not taking questions at his resignation press conference a day earlier.

During his ABC Radio Adelaide interview, Speirs discussed The Advertiser’s coverage of his leadership after it reported he was “forced to cancel plans” for a trip to Scotland this month – an account Speirs disputes.

“It’s in the best interests of my party to have someone that can keep that paper onside,” Speirs said.

“I was trying to lead the party and put forward an alternate vision for South Australia – if you can’t do that through the daily newspaper, half the battle’s gone.

“That’s on me in a way.

“Maybe… I should have taken them out for lunch more often.”