Tim Farron, a Liberal Democrat MP and former leader of that party, has tweeted his surprise at the length of Edwin Poots' time as DUP leader.

Mr Farron led the Lib Dems for two years, but resigned after poor General Election results in 2017.

Enda McClafferty
BBC News NI political editor

For 21 days Edwin Poots was living the dream, leading the party his father helped found and he joined as a teenager.

His DNA was DUP.

But nobody could have predicted how quickly the dream would turn sour.

He grabbed power by insisting he would be a listening leader for his fellow MLAs who had felt their voices weren’t heard during the Foster years.

But ironically his downfall was sealed when those same MLAs were ignored by their new leader.

They demanded that Edwin Poots stall the nomination of Paul Givan as first minister - but he didn’t listen.

His fate was sealed and his dream was short lived.

Sinn Féin has said the that whoever leads the DUP is a "matter for that party."

In a statement reacting to the resignation of Edwin Poots, the party said that their priority was "our response to the Covid19 pandemic, the continued successful roll out of the vaccination programme and rebuilding our economy to sustain jobs and livelihoods."

They added: “We have monumental challenges ahead that will require unity of purpose and urgency. They include tackling the totally unacceptable hospital waiting lists that have left people crucified, in pain and without hope.

“That is our focus and should remain the focus of all ministers in the Executive.”

Alliance MLA Paula Bradshaw has tweeted that whoever succeeds Edwin Poots must learn "that playing hardball gets them nowhere".

"The challenge is to work with the rest of us to deliver progress for all, not to circle the wagons."

Jayne McCormack
BBC News NI political correspondent

Mr Poots arrived at the party's headquarters sullen - aware his position had become untenable.

Four hours later he left, saying nothing.

The other party officers followed and within minutes came confirmation that he was resigning.

In a statement, he said he had asked the party chairman Lord Morrow to commence an electoral process to allow his successor to emerge.

He said it had been a difficult period for the party and the country.

It's been a more difficult period for him, facing battles every day of his short lived leadership.

He will remain in post until his successor takes over and said he wanted Northern Ireland to move forward to a stronger place.

The question now is can the DUP.

We spoke too soon - that's not all from us tonight. In a dramatic move, Edwin Poots has resigned as DUP leader.

That is all from us and thank you for joining on a momentous, and rather unpredictable, day in Northern Ireland politics.

Paul Givan and Michelle O'Neill are the first and deputy first ministers and a new look executive has held its first meeting.

Image source, Pacemaker

On a normal news day, that would be the headline, but in the context of DUP internal divisions and what they could mean for both the party and the executive, there could be more developments to follow.

Stay with BBC News NI's digital team for the latest and join The View on BBC One NI at 22:55 BST for more reaction.

Thursday's events began in the early hours.

After late night talks, Brandon Lewis emerged from Stormont House just before 01:00 BST to confirm that if the executive did not legislate for Irish language provisions, then Westminster would.

This ended a stalemate which in recent days appeared to threaten the future of Stormont.

So, at lunchtime, Paul Givan was confirmed as first minister, Michelle O'Neill as deputy first minister, and a new executive held its first meeting in the afternoon.

However, this is far from the full story.

DUP MPs and MLAs were reportedly in open revolt with the decision to nominate a first minister, with a meeting before the confirmation described as "mayhem".

A sizeable majority are believed to have voted against, but leader Edwin Poots pressed on.

This has led to public criticism of his leadership and talk that a vote of no confidence would be held later in the day.

At present, with the DUP locked in a crisis meeting, it is not known if this vote will happen- or what will come next.

Enda McClafferty
BBC News NI political editor

Edwin Poots is a leader under massive pressure tonight.

It was pretty clear from his expression as he arrived at Dundela House (DUP headquarters) within the past hour that he was clearly a man preparing for confrontation.

It's a big contrast to the last time he was there, because that was the scene of his great victory whenever he became leader.

On that occasion he said it was a good day for democracy within the DUP.

I'm not sure he will share that same analysis if there is a vote of confidence in his leadership tonight because we understand the numbers are stacked very much against him.

If that happens that will not automatically trigger his removal, but it might set in motion a sequence of events which could ultimately see that happen.

Jayne McCormack
BBC News NI political correspondent

We don't know if the process of a vote of no confidence is happening, we don't know if it's happened, we don't know an awful lot right now.

What we do know is if there's a motion of no confidence, it will be difficult for Edwin Poots to survive.

One senior party source spoke to me earlier and said now was the time to trigger Edwin Poots' removal - I think that is a pretty damning statement and I think Mr Poots finds himself in a difficult and lonely situation tonight.

With today's dramatic events set to run into the evening, tonight's The View is sure to be key viewing. Here's what the programme has coming up later...

Following our earlier football analogies that Edwin Poots may have 'lost the DUP dressing room', a BBC News NI political correspondent recalls Brian Clough.

The former Leeds manager famously alienated many of the club's top stars before he was dismissed after 44 days.

Edwin Poots became DUP leader on 28 May, 20 days ago.

Stephen Walker
BBC News NI Political Correspondent

The success and future of the Northern Ireland Executive are linked to the parties that are part of that the executive.

If you have one of those parties going through turmoil, which is clearly what is going on today, then that does have a impact on the executive and it could have an impact on power sharing.

There was an appeal from other parties today, particularly from people like Nichola Mallon of the SDLP, that said people in Northern Ireland are fed up with having a political crisis.

Michelle O’Neill was asked about the crisis within the DUP, and she said that is a matter for the DUP.

There is no doubt about it, when you have a crisis taking place in a party that is part of a power-sharing executive then there is a knock-on effect.

Many within the wider unionist and loyalist community will be left “aghast” by today’s developments within the DUP, loyalist activist Moore Holmes tells the BBC.

Speaking on Evening Extra he said the DUP “are in very dangerous territory” and that Stormont “feels like a boat with a hole in it”.

“They (the DUP) have drove themselves down another dead end, in my opinion, they come across as slightly rudderless,” he said.

Image source, PA Media

“I don’t underestimate their powers of recovery, but after another concession to Sinn Féin it’s hard to see how Poots can remain in the position he is in”.

He said despite Mr Poots standing for the party leadership on a ticket of “engaging with the loyalist and unionist community” the DUP leader has gone “in a direction that I would argue doesn’t have the support of the unionist or loyalist community”.

Most people entering DUP HQ for today's meeting have been fairly tight-lipped, but MP Sammy Wilson did stop to speak to the press.

When asked if there would be a vote of no confidence, he replies: "Any leader who didn't have the confidence of their assembly group and their MPs would find it very difficult to stay in position."

He adds: "You can't lead people who are not following you, so if you've no followers you can't be a leader, can you?"

Earlier we reported that a planned easing of Covid-19 restrictions in Northern Ireland has been pushed back to July 5 - here's more detail on that story.

Last week, the NI Executive outlined a number of indicative dates, external, which were due to be ratified on Thursday.

The relaxation of rules would have included resumption of live music along with removing the cap on outdoor gatherings and other measures.

Image source, Getty Images

It is thought the shelving is due to concerns around the Delta variant.

The number of Delta variant Covid cases has more than doubled in Northern Ireland over the past week.

The executive will review the situation on 1 July with a view to making changes on 5 July.

Read more.

Jayne McCormack
BBC News NI political correspondent

Just over a month since he was elected leader of the party, Edwin Poots has entered party headquarters tonight looking very sullen as those crisis talks got under way.

I think it is fair to say we do expect some sort of motion of no confidence to play out.

There is real anger at every level of the party over what has unfolded over the last 24 hours.

The question is - if there is a vote of no confidence tonight and Edwin Poots loses it, what happens then?

On the basis of conversations I’ve had today that doesn’t necessarily mean that Edwin Poots is all of a sudden out as party leader.

It is over then to the wider party executive to decide. It is scheduled to meet again next Thursday.