It was a major victory for UK Prime Minister Rishi Sunak, who managed to do what his predecessors had failed so miserably to secure – a deal with Brussels.

But the deal is not yet fully over the line, as Sunak still needs to appease and get the backing from some Conservative party members and Northern Ireland’s politicians – especially the Democratic Unionist Party (DUP) members.

Monday Recap

On Monday, both the UK and the European Union sealed a deal to resolve their strained post-Brexit trade dispute over Northern Ireland.

EU Commission Chief Ursula von der Leyen traveled to England to iron out a deal with Sunak over the contentious Northern Ireland Protocol – with both sides agreeing they were starting “a new chapter” together.

The agreement, known as the Windsor Framework, will allow goods to flow freely to Northern Ireland from the rest of the UK, end disputes that has jarred UK-EU relations, sparked the collapse of the Belfast-based regional government and shaken Northern Ireland’s decades-old peace process.

Addressing the House of Commons on Monday evening, UK Prime Minister Rishi Sunak said the UK and the EU had made a “decisive breakthrough”.

"After weeks of negotiations today, we have made a decisive breakthrough. The Windsor Framework delivers free-flowing trade within the whole United Kingdom. It protects Northern Ireland's place in our union and it safeguards sovereignty for the people of Northern Ireland,” Sunak said.

But that’s only half the battle

Now Sunak must sell the deal to his Conservative party members and his Northern Ireland allies. This might be a more difficult struggle.

The DUP has boycotted Belfast’s region power-sharing government with Sinn Féin until trade arrangements are changed to its satisfaction.

Northern Ireland is the only part of the UK which shares a land border with an EU member, the Republic of Ireland. When the UK left the bloc in 2020, the two sides agreed to keep the Irish border free of customs posts and other checks because an open border is a key pillar of Northern Ireland’s peace process.

But this angers unionist politicians, who argue that the arrangement undermines its position in the UK. Firstly, there are checks on some goods entering Northern Ireland from the rest of the UK. Secondly it meant Northern Ireland was still subject to EU law.

In reaction to Monday’s agreement between London and Brussels, DUP party leader Sir Jeffrey Donaldson said: “In broad terms, it is clear that significant progress has been secured across a number of areas, whilst also recognising that there remain key issues of concern. There can be no disguising the fact, for example, that in some sectors of our economy in Northern Ireland, EU law remains applicable in our part of the United Kingdom."

Nationalist party Sinn Féin wants to see a return to restoring power-sharing as quickly as possible.

"What I've said consistently throughout the whole of the Brexit debate is that the people here have been left in limbo,” said First Minister Michelle O'Neill. “They've left with uncertainty. I'm hoping that today [Monday], because we're at the end of the negotiation, the deal is now done."

Getting his own party on board

Lastly, Sunak must win the support of his own party internally. The Prime Minister had gone on somewhat of a charm offensive to sway the staunch Tory Brexiters to persuade them to agree to the deal – arguing that further delays to the NI Protocol would be electoral suicide.

It was rumoured last week, that as many as 100 Tory members could rebel against their prime minister. But Tory whips are hopeful that it can be limited to two dozen MPs, meaning Sunak would not have to rely on opposition party Labour’s votes, who have said they will back the UK-EU deal.

Reaction

Monday’s outcome has been largely hailed positively between Dublin, Belfast, London and Brussels.

Irish Prime Minister Leo Varadkar said the announcement of a positive outcome in negotiations on the Northern Ireland Protocol between the EU and the UK is most welcome.

“It is the result of a long protracted process to find joint solutions, and I pay tribute to both teams who`ve worked hard and in good faith to bring us to this point.”

The White House was also pleased with the outcome. US President Joe Biden praised the new Windsor Framework arrangement.

He said: “I appreciate the efforts of the leaders and officials on all sides who worked tirelessly to find a way forward that protects Northern Ireland’s place within the UK’s internal market as well as the EU’s single market, to the benefit of all communities in Northern Ireland.

“I am confident the people and businesses of Northern Ireland will be able to take full advantage of the economic opportunities created by this stability and certainty, and the United States stands ready to support the region’s vast economic potential.”