Boris Johnson has said his plan to legislate to rip up Northern Ireland's post-Brexit trading arrangements was an "insurance" policy if a fresh deal could not be reached with the European Union.
The Prime Minister travelled to Northern Ireland on Monday to meet leaders of the Stormont parties in an attempt to secure progress - but also used the trip to issue a warning to Brussels that the UK is ready to rewrite unilaterally the terms of the Brexit deal he signed.
Mr Johnson is frustrated that talks with Brussels to resolve the protocol problems have not made sufficient progress. The move could risk a trade war with the EU.
"None of the parties - I spoke to all five parties just now - not one of them likes the way it's operating, they all think it can be reformed and improved," the Prime Minister told reporters.
Mr Johnson said "we would love this to be done in a consensual way with our friends and partners" in Brussels, "ironing out the problems, stopping some of these barriers" to goods crossing the Irish Sea from Great Britain.
"But to get that done, to have the insurance, we need to proceed with a legislative solution at the same time."
Foreign Secretary Liz Truss is expected to set out plans for legislation to rewrite the protocol when she addresses MPs at Westminster on Tuesday, according to reports.
It comes after the parties criticised the Prime Minister following meetings at Hillsborough Castle.
Mr Johnson has said he urged the DUP to get back into government and to nominate a Speaker following a meeting with Northern Ireland’s main parties on Monday.
Addressing the media at the Thales factory in Belfast he said he told the DUP: “We want to see you back in the Executive. We want to see you nominating. We want to see a Speaker in the Assembly”.
DUP leader Sir Jeffrey Donaldson reiterated his view that the time for talking is over as he urged the Government to take action on the NI Protocol after a meeting with the Prime Minister.
Sinn Fein president Mary Lou McDonald described a meeting with Prime Minister Boris Johnson as “fairly tough”, claiming the Government’s priority is “placating the DUP”.
She also accused the Government of co-ordinating the current impasse alongside the unionist party.
The DUP is refusing to nominate a speaker to allow the Assembly to function, or a deputy First Minister to allow the Executive to be formed, until the UK takes action on post-Brexit trading arrangements which unionists regard as a border in the Irish Sea.
South Belfast MLA Edwin Poots and East Belfast MP Gavin Robinson were also part of the delegation with the Prime Minister in Hillsborough Castle.
Sir Jeffrey said: “We have been reasonable and patient. The Government has known what is needed. We published our seven tests in July last year.
"Our tests were not grounded in a unionist wish list, but in promises already made in one form or another, to the people of Northern Ireland. It’s time for the Government to stand over those promises.”
On the other hand, Sinn Fein’s Mary Lou McDonald said it is “very clear to us that despite all of the rhetoric from the British Government about re-establishing the Executive here in the north, that in fact their priority is placating the DUP.”
Ms McDonald added: "We've had what we would describe as a fairly tough meeting with the Prime Minister.
"We have put it to him very directly that the absolute priority is getting government working here in the north. We have said directly to him that proposed unilateral act of legislating at Westminster is wrong.
"We have told him very clearly that we are here to do business. The people have spoken. We have had the election, the votes have been counted, the die has been cast. Michelle O'Neill is the first minister in waiting and we want to get on with things and get back to business.
"I'm sorry to report that we've had no straight answers really from the British Prime Minister except a confirmation of what we already knew, which is that in fact this impasse is entirely co ordinated between themselves and the DUP, and if the DUP are acting shamefully in holding back government, well then the British Government is behaving even more shamefully."
The Alliance Party described a meeting with Prime Minister Boris Johnson on Monday as "robust and very frustrating".
Deputy leader Stephen Farry said: "We were giving him a very clear warning that if he plays fast and loose with the Protocol and the indeed Good Friday Agreement, then he is going to be adding more and more instability to Northern Ireland.
"On the one hand, he is coming here with a certain set of stated outcomes, but all his actions belie what he is notionally trying to achieve."
SDLP leader Colum Eastwood said that while he welcomes the Prime Minister's call for the resumption of power-sharing, the gulf between Boris Johnson’s actions over the last two years and his words on Monday are so great that it makes it “impossible to trust” him.
“This farce cannot continue. People need and deserve the power of government working to address the challenges they face. It is time for the DUP to work with the rest of us to restore Stormont and get on with the job that people elected us all to do.”
Meanwhile, protestors gathered in Hillsborough, Co Down ahead of the Prime Minister's visit and booed and jeered his cavalcade as it drove through the gates of Hillsborough Castle.
Protesters, numbering around 200, held banners which read "Back off Boris. Protect The Protocol".
There was also a demonstration by some of the families of the 11 people killed by soldiers in Ballymurphy in west Belfast in 1971 against plans by Government to offer an effective amnesty to prosecution for Troubles offences.