(Bloomberg) -- Northern Ireland’s Democratic Unionist Party said its lawmakers will unanimously vote against Rishi Sunak’s post-Brexit deal for the region, in a significant blow to the UK prime minister.

Members of Parliament are set to hold their first vote on Wednesday on the new agreement, which was announced last month by Sunak and European Commission President Ursula von der Leyen. The new trading arrangements are designed to ease the flow of goods from Great Britain to Northern Ireland, and give that region’s politicians a greater say in the application of EU laws.

But DUP leader Jeffrey Donaldson said on Monday that his party’s officers had “unanimously agreed” to oppose the deal in Wednesday’s vote, while “continuing to seek clarification, change and re-working” of its provisions.

The stance by the DUP suggests there’s no end in sight to the political impasse in Northern Ireland, where the region’s devolved government has been suspended for more than a year. The party has refused to participate in a power-sharing executive until its concerns about the Brexit deal are addressed. 

Asked by reporters if the DUP’s failure to support Sunak’s deal means that power-sharing will not resume, Donaldson told reporters on Monday that “I don’t believe that what we have at the moment is sufficient.”

Rebel Tories

“We need to ensure that whatever arrangements are put in place they provide the stability that Stormont needs on a cross-community basis to operate effectively,” he added. 

The DUP stance is a blow to Sunak, who had hoped to win them around after securing improvements to the deal negotiated by fellow Conservative former Prime Minister Boris Johnson. 

With the opposition Labour Party pledging backing Sunak’s plans, the DUP’s eight MPs won’t dent his chance of winning Wednesday’s vote — but their opposition may trigger a rebellion by pro-Brexit allies in the ruling Tories.

Sunak has a working majority of 66 in Parliament, meaning it would take at least 33 rebels to leave him relying on opposition votes.

‘Breakthrough’ Deal

Sunak and von der Leyen last month hailed their agreement — called the Windsor Framework — as a “decisive breakthrough,” describing it as a way to end years of acrimony since the UK left the bloc in 2020. 

Read More: What’s the ‘Windsor Framework’ for Northern Ireland?

Since then, all eyes had been on whether the DUP — and hard-line members of Sunak’s Conservatives — would back the deal. The Tory Party’s Brexiteer faction, known as the European Research Group, is due to get its legal advice on the deal on Tuesday, a person familiar with the matter said.

Wednesday’s vote won’t be on the whole agreement, but rather on a piece of legislation known as a statutory instrument that’s focused on the so-called Stormont Brake — a portion of the deal that aims to give Northern Ireland’s lawmakers a potential veto over changes to EU rules. 

The brake was designed to challenge amendments or replacements to EU law. That rankled the DUP, which said it “therefore cannot apply, to the EU law which is already in place and for which no consent has been given for its application.” 

That “does not deal with the fundamental issue which is the imposition of EU law” by the existing arrangements, the party said.

The UK government argues that the devolved government in Stormont has a vote on post-Brexit arrangements by the end of 2024 and every four years thereafter, which is how it could reject the inherited framework of EU legislation. 

“We continue to believe this is the best deal for the businesses of Northern Ireland, Sunak’s spokesman Max Blain, told reporters on Monday. “We understand there will be a range of views,” he said, adding that the prime minister is “confident” the Commons will back his deal.  

--With assistance from Morwenna Coniam.

(Adds comment from Donaldson on Northern Ireland’s power-sharing government in fifth paragraph.)

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