Edwin Poots has resigned as leader of the Democratic Unionist Party (DUP) after just 21 days in the post.
Mr Poots was forced out on Thursday night (17 June) following a revolt within his party over a deal struck with Sinn Féin and the nomination of Paul Givan as Northern Ireland’s First Minister.
There are fears that the leadership meltdown in the country’s biggest party could threaten the future of power-sharing at Stormont.
So, why has Edwin Poots resigned from the DUP - and who might replace him?
Here is everything you need to know.
Why has Edwin Poots resigned from the DUP?
That meant both a new First Minister and Deputy First Minister had to be appointed within a week, unless a Stormont election would be called.
Before Sinn Féin agreed to nominate their own Deputy First Minister, the party demanded a commitment to put Irish language legislation in place.
Early on Thursday morning, a deal was reached, with Secretary of State for Northern Ireland Brandon Lewis declaring that legislation would be brought in by Westminster by October if not first introduced at Stormont.
The deal was designed to rectify a stalemate with Sinn Féin.
Both the Sinn Féin and DUP leaderships then nominated candidates, despite a significant majority of DUP members in the assembly wanting to delay the process.
After Mr Poots formally nominated Paul Givan as Northern Ireland’s new First Minister, an emergency meeting of DUP party officers was held in Belfast on Thursday evening, following speculation that a revolt to oust him could be set in motion, with the party leader potentially facing a vote of no confidence.
Some DUP representatives were angry that Mr Poots had pressed ahead with nominating Mr Givan after Sinn Féin secured the concession from the UK Government over Irish language laws.
The members were unhappy that Mr Poots had agreed to enter a coalition on that basis.
Party sources told the BBC that the meeting was “robust”, and said it had become clear that Mr Poots knew he had to resign.
The UK Government had been warned by DUP politicians about getting involved in such a sensitive, devolved issue.
What did Mr Poots’ statement say?
Mr Poots will stay in his post until a successor is elected. He becomes the shortest-serving leader in the DUP’s history.
Speaking on Thursday evening, Mr Poots said: "I have asked the party chairman to commence an electoral process within the party to allow for a new leader of the Democratic Unionist Party to be elected.
"The party has asked me to remain in post until my successor is elected.
"This has been a difficult period for the party and the country and I have conveyed to the chairman my determination to do everything I can to ensure both Unionism and Northern Ireland is able to move forward to a stronger place."
Who will replace him as DUP leader?
It is understood that the process to appoint Mr Poots’ successor could move quickly, potentially within the next few weeks.
Sir Jeffrey Donaldson, the DUP’s Westminster leader and the longest-serving MP from Northern Ireland, is an early frontrunner to replace him as DUP leader.
Mr Poots, who took over as leader from Ms Foster in May, narrowly defeated Sir Jeffrey in a leadership vote by only two votes.