The Prime Minister and the European Commission President announced the news at a press conference in Windsor
Rishi Sunak has said his “decisive breakthrough” on post-Brexit rules will remove trade barriers for Northern Ireland and give the UK a “veto” on EU law as he seeks the backing of unionists.
The Prime Minister hailed the controversially named “Windsor Framework” as marking a “new chapter” on relations with Brussels that he hopes will restore powersharing in Stormont.
But European Commission president Ursula von der Leyen said the replacement to the Northern Ireland Protocol still includes a role for the European Court of Justice – a key issue for the Democratic Unionist Party (DUP).
The pair finalised the long-awaited deal to improve the agreement signed by Boris Johnson more than three years ago after a meeting in Windsor lasting under two hours.
The EU chief went on to have tea with the King at Windsor Castle, despite criticism that the meeting would drag Charles into the politically contentious agreement.
DUP leader Sir Jeffrey Donaldson welcomed “significant progress”, but said that “there remain key issues of concern” including the remnants of EU law as his party considers its next step.
Mr Sunak said Parliament will “have a vote at the appropriate time”, and “that vote will be respected” after coming under pressure to give MPs a say on the deal.
A key part of the deal is an emergency “Stormont brake” on changes to EU goods rules that can be pulled by the Northern Ireland Assembly that Mr Sunak said would give the Westminster Government a “veto”.
The Prime Minister said it is a “very powerful mechanism” for Stormont to use when it has concerns over EU law.
At a press conference in Windsor Guildhall, the Prime Minister said: “I’m pleased to report that we have now made a decisive breakthrough.
“Together we have changed the original protocol and are today announcing the new Windsor Framework.
“Today’s agreement delivers smooth-flowing trade within the whole United Kingdom, protects Northern Ireland’s place in our union and safeguards sovereignty for the people of Northern Ireland.”
Mr Sunak said he believes the deal is a “turning point for Northern Ireland” that addresses the concerns of the DUP, and is now hoping they will back it and restore powersharing in Stormont.
Standing beside the Prime Minister she warmly referred to as “dear Rishi”, Ms von der Leyen hailed a “new chapter in our partnership” that will foster a “stronger EU-UK relationship”.
She said Brussels will immediately start the ball rolling on the UK joining the EU’s Horizon scientific research programme, marking a clear thawing of the tensions most visible under Boris Johnson.
Mr Sunak will scrap his predecessor’s controversial legislation to override parts of his own protocol deal, and in turn Brussels will end its legal action against the UK.
The support of the DUP, which collapsed powersharing last year over the protocol, be crucial for winning the backing of Conservative Brexiteers in the Commons.
Conservative Brexiteer Jacob Rees-Mogg warned Mr Sunak of a possible Tory revolt if the DUP does not support the deal, despite major concessions from the EU.
The former cabinet minister told GB News: “It will all depend on the DUP. If the DUP are against it, I think there will be quite a significant number of Conservatives who are unhappy.”
He said that the position of Mr Johnson, who he described as the “biggest figure in UK politics”, will be “fundamental”.
But arch-Brexiteer Steve Baker, the Northern Ireland Office minister who had been on resignation watch, gave Mr Sunak his support over the “really fantastic result”.
He told the BBC that “reasonable unionists” will support the deal, while those who “would dig a moat between the North and the South” will “never be happy”.
Labour leader Sir Keir Starmer confirmed his party will support the deal, meaning Mr Sunak is bound to win the Commons vote, but he will want to succeed without relying on the Opposition.
Charles’s meeting with Ms von der Leyen was criticised as “constitutionally unwise” by Mr Rees-Mogg because it involves the King “in a matter of immediate political controversy”.
Baroness Arlene Foster, the former DUP leader and ex-first minister of Northern Ireland, said it was “crass and will go down very badly” with the unionists Mr Sunak is trying to win over.
Mr Sunak will travel back to London to make a statement to MPs.
Tory Brexiteers in the European Research Group (ERG) are to meet on Tuesday and will convene MP Sir Bill Cash’s so-called “star chamber” of lawyers to scrutinise the deal before deciding whether to back it.
The protocol was designed to prevent a hard border with Ireland after Brexit but means Northern Ireland has continued to follow EU rules on goods to prevent checks being needed when crossing into the Republic.
Unionists’ anger over the trade barriers in the Irish Sea culminated in the DUP collapsing powersharing in February last year, leaving Northern Ireland without an executive or an assembly.