Friday’s hotly anticipated showdown over the leadership of the Liberal Party is now definite – confirmed with a tweet from embattled Prime Minister, Malcolm Turnbull.

“I have just been provided with a request for a meeting of the parliamentary Liberal Party,” Mr Turnbull wrote at 11.30am (AEST) on Friday.

“It has 43 signatures. As soon as they are verified by the whips, which should not take long, the meeting will be called.”

Mr Turnbull’s announcement came only a few minutes after leadership challenger Peter Dutton presented him with the 43-signature petition he had demanded ahead of a second spill of the Liberal Party’s leadership this week.

I have just been provided with a request for a meeting of the Parliamentary Liberal Party. It has 43 signatures. As soon as they are verified by the Whips, which should not take long, the meeting will be called.

— Malcolm Turnbull (@TurnbullMalcolm) August 24, 2018

Earlier, the nation’s top lawyer provided legal advice that paved the way for Peter Dutton to challenge Mr Turnbull.

Solicitor-General Stephen O’Donaghue QC handed written advice to Mr Turnbull and Mr Dutton on Friday morning, saying he believed was no legal impediment to the would-be PM sitting in parliament.

The legal opinion and the petition were the last hurdles before an expected three-way contest at a party room meeting to replace Mr Turnbull as Liberal leader from midday (AEST) on Friday.

Also expected to challenge are Treasurer Scott Morrison and Foreign Minister Julie Bishop.

At that meeting, Mr Turnbull has indicated he will step down as party leader and prime minister.

Attorney-General Christian Porter had asked Mr Donaghue to prepare an advice on the member for Dickson’s eligibility to sit in parliament. It followed questions about income that Mr Dutton receives from a family trust, derived from child care centres that receive government subsidies.

Section 44 of the constitution states that any person who has any direct or indirect pecuniary interest in any agreement with the Commonwealth is ineligible to be chosen or of sitting as a senator or MP.

The advice from Mr O’Donaghue on Friday was that Mr Dutton is “not incapable of sitting as a member of the House of Representatives by reason of section 44 of the Constitution”.

The tl;dr of the Solicitor-General's advice:

– Dutton should be fine
– But he can't be 100% certain
– He doesn't have all the facts before him
– He's cautious about the High Court taking a different approach
– The facts here are different to Bob Day@politicsabc #auspol

— Matthew Doran (@MattDoran91) August 24, 2018

However, Mr O’Donaghue said he could not be certain that there was no breach.

“I consider there to be some risk, particularly in light of the substantial size of the payments that appear to have been made by the Commonwealth to RHT Investments (the Dutton family trust), that the High Court might conclude that there is a conflict between Mr Dutton’s duty as a parliamentarian and his personal interests,” he wrote.

He said he had “been briefed with very little factual information” on Mr Dutton’s potential breach of the constitution

“I provide my opinion on the basis of my present understanding of the facts … If the facts turn out to be materially different to those stated, my opinion will need to be revisited,” he said.

Ultimately, only the High Court can finally decide on the issue.

Mr Dutton later released a statement saying the “consistent and strong advice” he had received put “to rest the false, unsubstantiated and malicious claims regarding my eligibility to sit as a member of Parliament”.

Read the full version of Mr O’Donoghue’s opinion here.

More to come