Labor powerbroker Don Farrell has withdrawn his candidacy for preselection in a safe Labor seat after Premier Jay Weatherill threatened to resign.

Weatherill made it clear on ABC radio this morning that he would quit if Farrell was successful in his bid to replace Cabinet minister Michael O’Brien in the northern Adelaide seat of Napier.

Farrell initially refused to back down saying he would seek preselection next week.

However, at an 11am press conference Farrell said he would withdraw his candidacy for preselection in the best interests of the party – and retire from politics. O’Brien said he would likely resign from cabinet.

“Politics is the art of the possible,” he said. “Jay has made it very clear that he doesn’t support me in this. I do support the Labor Party, I do support Jay. I don’t want to see what’s happening federally happen in SA. I think the best thing I can do to support stability … is for me to withdraw my candidacy.”

He said his political career would end when his Senate term ends on June 30.

“When my term finishes I shall play no further part in public life, either state or federal.

“I’ve made my decision, I’ve made my decision to withdraw, and I have no regrets about that.”

Earlier, Weatherill said Farrell was associated with divisions in the federal party which “destroyed” the Rudd Labor Government and he did not want this in South Australia.

When asked if he would resign if Farrell was preselected, Weatherill said: “I would have to reflect on that, of course.”

Farrell immediately told ABC breakfasts that he would plough on and seek preselection, later changing his mind as the party went into meltdown behind closed doors.

For his part O’Brien called for Weatherill to withdraw his threat, saying that Farrell’s bid for preselection had widespread support in the party’s dominant right faction.

“Everybody involved in this particular issue needs to give 24 hours at least to determine a clear course of action,” O’Brien said.

“I do think that the position is salvageable. Don has no designs on Jay’s position. Don will make a significant contribution.

“That’s the misconception, that this is a right-wing plot. This discussion has up until this morning been a discussion between Don and myself. The phone calls that I have received indicate widespread support by significant players in the right for what Don and I are doing.”

Asked whether he believed he could continue to serve in Weatherill’s cabinet, O’Brien said: “Let’s give it a good day for things to settle down and then it will all become clearer and I believe at lot more stable.”

O’Brien said he believed the whole issue would quickly blow over and be forgotten well before the March 15 election.

“Our view is it would probably be a 24 hour wonder and then things would move on.”

Adelaide University head of politics Clem Macintyre described the Weatherill ultimatum as “gobsmacking”.

“It’s extraordinary; a declaration of war within Labor that sounds pretty uncompromising,” he told InDaily.

“It (the State Election) is no longer in doubt.”

Farrell, who failed to be re-elected to the Senate at least year’s federal election, is the leader of the dominant right faction in South Australia and was a key player in the Rudd-Gillard leadership battles – one of the so-called “faceless men” who brought down Kevin Rudd.

O’Brien, the member for the northern Adelaide seat of Napier who holds a number of portfolios including Finance and Police, told ABC radio’s breakfast program this morning that he had spoken to Farrell the day after the federal election and offered to give up his seat for him.

He denied that the move was any threat to Weatherill, who is from the left faction.

He said he made the offer to Farrell on the day after the election when it became apparent that Farrell was likely to lose his Senate seat.

Farrell, a long-term friend, would be “a great loss to public life”, O’Brien said.

He said Weatherill was aware of the move.

“Don and I met with Jay probably a week ago,” he said.

“We had coffee with him one morning and we discussed this.”

A report in The Australian this morning, which broke the story, said that the right faction planned for Farrell to become Opposition Leader should Labor lose the state election.

O’Brien said Farrell would make a good leader but “that’s not his desire”.

“Don’s focus is getting to grips with representing a constituency,” O’Brien said.

Later, O’Brien told FIVEaa that the move was meant to be announced on Monday but it had been leaked to the media.

Farrell told the radio station he had considered O’Brien’s offer and decided he had something to offer the people of Napier and the state.

“I would very much like to be part of the next Weatherill Government,” he said.

He said he had “no ambitions to lead the Labor Party”.

“I supported Jay in the job, and I continue to support him, and I will will continue to support him after the election…”

When asked how Weatherill reacted to his plans, Farrell said: “I can assure you that Jay has no concerns about my leadership ambitions.”

“This is not about leadership – it’s about supporting Jay and the rest of the Labor Party team…”

Napier, based in the outer northern suburbs, is one of Labor’s safest seats.

This article first appeared on InDaily.