Prime minister Boris Johnson is set to attend crunch talks in Belfast today ahead of plans to scrap swathes of the Northern Ireland Protocol.

Delivering a “tough message” in private meetings on his first visit to Belfast since the Assembly elections, Johnson is expected say that – while the UK government will “play its part to ensure political stability” – any action to fix the Protocol must result in all parties coming together to form and Executive and Assembly.

Drawing on his time as Mayor of London, Johnson will say that there is “no substitute for strong local leadership”. Legislators must “get back to work” so that they can deal with the “bread and butter issues” like supporting families with the cost of living, cutting Covid backlogs and fighting crime.

The PM will update party leaders on the UK government’s discussions with EU leaders over recent days, in which the EU have confirmed that they will never change their current negotiating mandate.

He will tell party leaders “that we will always keep the door open to genuine dialogue” however “there will be a necessity to act” and protect the Belfast (Good Friday) Agreement if the EU does not change its position.

The PM will argue that the government has never suggested scrapping the Protocol. There will always have to be a treaty governing the UK’s relationship with the EU in respect of Northern Ireland in order to prevent a hard border on the island of Ireland and protect the integrity of the EU single market.

Johnson will stress that the Protocol needs to be reformed so that it delivers on its initial objectives to protect the Belfast (Good Friday) Agreement in all its dimensions.

He will say that there is “no disguising the fact” that the delicate balance of the Agreement has been upset by the Protocol, because one strand of the Agreement (North-South) has taken precedent over another (East-West).

Johnson will argue that this undermines the text of the Agreement, which makes clear that all strands are of “interlocking and of equal importance”. It has eroded the historic economic bonds which link Great Britain and Northern Ireland and resulted in the Unionist community feeling like its aspirations and identity are threatened.

The UK and EU’s “shared objective” should be for a reformed Protocol to enjoy “the broadest possible cross-community support” when it faces a consent vote in 2024, he will say.

In an article published by the Belfast Telegraph ahead of his visit, Johnson says the Protocol row is limiting Westminster’s ability to help ease the cost-of-living crisis, and that a UK-wide VAT cut on renewable has not been possible because of it.

He cited Covid and the Russian invasion of Ukraine as responsible for ” a cost-of-living crisis on a scale not seen for half a century”, which the Protocol, negotiated back in 2019, was not equipped to manage.

Tomorrow, foreign secretary Liz Truss is set to announce legislation to unilaterally suspend swathes of the post-Brexit deal amid warnings it could spark an EU-UK trade war.

Home Office minister Rachel Maclean told Sky News this morning that Truss’ plans did not risk breaching international law, stressing: “Of course there are always going to be measures that have to be negotiated and I think that is the point of a negotiation with our European partners.

She went on: “This has been going on at pace with officials, with our interlocutors on the European side and as far as the subsequent actions that are going to be taken, a lot of it is speculation. But of course the UK is a country that always lives up to its international legal obligations and we will continue to do that.”

Former Conservative Northern Ireland secretary Julian Smith has advised against scrapping parts of the Protocol.

Speaking to BBC Radio 4’s Today programme this morning, he said: “I think there is a landing zone where east/west checks are more or less removed, where the regulatory divergence, the challenges that come of UK goods and EU goods in the same Northern Ireland market that there can be fudges there.

“I think we do need the EU and UK negotiators to spend some positive time in a locked room and come up with a deal. We need a political deal, we need a fudge,” he went.

Speaking to The Irish Times today, Sinn Fein vice president Michelle O’Neill, said that unilaterally scrapping parts of the Protocol would “represent an appalling attack on the international rule of law”.

“Only through joint agreement with the EU can solutions to problems or concerns be resolved. I will be telling Boris Johnson that unilateral action deepens political instability and economic uncertainty and must not happen,” she went on.

Irish foreign affairs minister Simon Coveney told journalists in Brussels this morning that such a move would prompt “legal challenges”, adding that: “this is a time for calmness, it’s a time for dialogue, it’s a time for compromise and partnership between the EU and the UK to solve these outstanding issues.

“If that is the approach taken by the British government then we can make significant progress and we can make progress quickly to respond to the concerns of both the business community and the unionist community in Northern Ireland.

“That alternative is unilateral action which means tension, rancour, stand-offs, legal challenges and of course calls into question the functioning of the TCA itself, because the TCA and the Withdrawal Agreement are interlinked, they rely on each other.”