The DUP should "immediately" reinstate a first minister to ensure the delivery of services in Northern Ireland, the Northern Ireland secretary says.

Brandon Lewis says it is "extremely disppointing" that Paul Givan has resigned and he warns against "a return to a state of political deadlock and inertia".

Mr Lewis says the UK government is fully committed to dealing with "serious problems" which have been caused by the Northern Ireland Protocol.

However, he says he hopes political leaders "will take the necessary steps to restore the stability in the devolved institutions that the people of Northern Ireland deserve".

Paul Givan's resignation as first minister will take effect from midnight, DUP leader Sir Jeffrey Donaldson confirms.

His resignation letter was submitted to the assembly's speaker this afternoon.

Paying tribute, Sir Jeffrey thanks Mr Givan "for the way he has undertaken his duties as first minister over the last eight months particularly in the midst of the pandemic".

The DUP leader confirms his party's other ministers will remain in post ahead of the assembly election and will work "where possible" to ensure legislation can pass through the assembly before a dissolution date is set by the Northern Ireland secretary.

Jayne McCormack
BBC News NI political correspondent

The Department of Health has confirmed that legal advice will be taken on how decisions on Covid-19 restrictions can be taken in the absence of an executive.

Health Minister Robin Swann has powers overseeing the regulations, but had never used them, instead taking all relevant Covid decisions to the executive.

However, as it is soon no longer going to be in place, it is possible he could act unilaterally to lift the remaining measures.

Image source, Pacemaker

They were due to be discussed at an executive meeting next Thursday, but this will no longer go ahead.

It is understood ministers were likely to agree to a large-scale lifting of most of the remaining regulations.

The Department says: “Advice will be taken on available options in the absence of executive decisions on Covid regulations.”

The regulations are due to expire on 24 March.

The leader of the DUP has accused the UK government of failing to "honour" its commitment to "protect Northern Ireland's place within the UK internal market".

Speaking following the resignation of the first minister, Sir Jeffrey Donaldson said the party had reminded the UK government of its "promises."

"This commitment was the basis upon which we re-entered the executive in early 2020 and have participated in the political institutions since then," he said.

"I warned that as leader of the DUP, I was not prepared to lend my hand to a protocol which so fundamentally undermines the union and the economic integrity of the United Kingdom and Northern Ireland's position in it."

Former DUP minister and current chief executive of Belfast Chamber Simon Hamilton tweets that "another period of political instability" is the last thing Northern Ireland needs.

Paul Givan thanks his family for their support during his time as first minister.

In an emotional speech, which lists many of the executive's priorities and achievements during his time in post, Mr Givan says it would not have been possible for him to carry out his role "without their support".

"It's often those that we're close to in our families who feel the pressure, even more so than those of us in frontline politics," he adds.

Paul Givan begins his resignation speech saying being first minister has been the "privilege of my life'.

He says when he entered the assembly in 2010 he never expected to be first minister.

He thanks Edwin Poots for nominating him for the job and Sir Jeffrey Donaldson for asking him to continue in the role.

Paul Givan has announced he will resign as first minister of Northern Ireland.

Michelle O'Neill said she had spoken to other party leaders to make progress on issues "at pace" while the DUP engaged in "stunt politics".

The deputy first minister, who will lose her role if Paul Givan resigns from the joint office this afternoon, said politics at Stormont "can't limp on forever".

Mrs O'Neill continued to say there would be "catastrophic impacts" as a result of the DUP's actions, such as a delay to the apology for victims of historical institutional abuse and knock-on effects for the draft budget and dealing with cost of living matters.

More on that call from Mary Lou McDonald for an early assembly election.

Northern Ireland is set to go to the polls in May, but this could be brought forward.

"This is one of those defining moments, we can do so much better than this chaotic theatre," Ms McDonald said.

She said the DUP's actions were about their "narrow and self-serving political interests" and not the Northern Ireland Protocol, which she said was "here to stay".

"The protocol is essential, the protocol is a consequence of Brexit, a Brexit that the DUP campaigned vigourously for," she added.

Ms McDonald said it was a "fallacy" to believe the protocol would be dispensed with.

Speaking ahead of the official announcement of Paul Givan's resignation as first minister, Sinn Féin has said the DUP's actions had consequences.

"We cannot stagger on in the months ahead without a functioning executive and Sinn Féin will not facilitate this," said party leader Mary Lou McDonald.

"So in the absence of a functioning executive an early election must be called and the people must have their say."

More to follow.

Alliance leader Naomi Long spoke to the BBC News Channel saying people in Northern Ireland were "exhausted and frustrated" by a state of constant crisis.

Jayne McCormack
BBC News NI political correspondent

What is it about the DUP, Thursday nights and a certain hotel on the outskirts of south Belfast?

The last time they met in such circumstances they were celebrating the party’s 50th birthday.

Image source, REUTERS/CLODAGH KILCOYNE

Just months before that, dramatic scenes erupted amid the fallout over the election of Edwin Poots as leader.

You could say they’re now back again for their leaving do - with Paul Givan tendering his resignation as Stormont’s first minister and sparking a fresh political crisis.

The resignation of Paul Givan as first minister is “another manufactured crisis”, according to Ulster Unionist Party leader Doug Beattie.

He says it will effect people in Northern Ireland who have “suffered enough and they are going to suffer more”.

“They will suffer in the medium term and they will suffer in the long term and all politicians should be standing here and everything that they do, they should be doing for the betterment of the people of Northern Ireland,” he tells reporters in Stormont’s Great Hall.

“For unionism, this is absolutely crazy,” Mr Beattie adds.

“If there's changes to the protocol in the coming weeks or months, it'll because of the hard work is done behind the scenes to get those through negotiations. It will not be done by a minister resigning from their post.”

The DUP’s actions represent a “total betrayal of the people”, SDLP leader Colum Eastwood says.

“We’re going through massive hikes in energy costs, our waiting lists are an embarrassment around the world, and the DUP are pulling their first minister out of government,” he tells the media in Londonderry.

The Foyle MP accuses the DUP of pulling a “stunt” which he says is more to do with the upcoming assembly election and not the Northern Ireland Protocol.

“I frankly think people have had enough of 15 years of in and out of government, of parties only focused on themselves and not focused on delivering for the people," he adds.

The DUP is “determined to wreak havoc on the rest of Northern Ireland” following months of internal unrest, the Alliance Party leader said.

Naomi Long told Talkback the party had “been like a slow-motion train wreck” for the past several months and had failed going from “strategy to strategy”.

Image source, Pacemaker

Describing the current situation as “cynical and contrived”, the justice minister accused the DUP of playing “nasty and unpleasant political games with people’s everyday lives”.

“I think it’s utterly shameful,” she continued.

As we wait for that announcement from Paul Givan, checks of goods are continuing to be made at sea ports in Northern Ireland.

This is despite an order from his Democratic Unionist Party (DUP) colleague for the checks to stop at midnight.

Image source, Pacemaker

Agriculture Minister Edwin Poots said the checks were set to be halted after receiving legal advice, with the decision made as part of the DUP's ongoing opposition to the Northern Ireland Protocol.

But a spokesperson from the prime minister's office said that the checks were continuing and that "we are reviewing the legal position".

Read more here.

The former head of the Northern Ireland Civil Service has said Stormont departments would be left in an "extremely difficult position" if Paul Givan resigns.

Speaking on BBC Radio Ulster's Talkback programme, Sir David Sterling explained what would happen next for the executive.

“It is a joint office so the executive would not be able to function," he said.

"Departmental ministers would stay in place although their ability to do anything new would be very circumscribed, they would largely just be able to keep their departments ticking over."

Image source, PA Media

He said the most significant issue was the budget, which has not been delivered for the next financial year beginning in April.

“Without a budget departments would be left in an extremely difficult position.

"They are already facing huge difficulties because they are unable to plan with any great degree of precision how they are going to manger their departments for next year," he told the programme.

“Never mind a one year budget, departments really need a three-year budget to be able to plan for the delivery of public services over the longer term.“

DUP leader Sir Jeffrey Donaldson arrives at the Crowne Plaza Hotel in south Belfast for a party meeting.

It is expected he will speak to the media following a resignation announcement by Paul Givan this afternoon.