It felt like a renewal of vows. Seven years after the rupture of the Brexit vote and the subsequent freeze in relations, a British prime minister and the president of the European Commission stood side-by-side at Windsor Guildhall, pledging to work amicably together.
In the 17th century wedding venue chosen by King Charles and Camilla, and by Sir Elton John and David Furnish, Rishi Sunak, UK prime minister, declared in a soft-focus press conference that Britain and the EU were “allies, trading partners and friends”.
Ursula von der Leyen, European Commission president, said the UK and the EU were “close partners, shoulder to shoulder, now and in the future”. The “Windsor framework” they agreed was a dense text about an overhaul of post-Brexit trading rules in Northern Ireland, but the significance was far greater.
For Sunak and von der Leyen this was a moment to reset UK-EU relations. Both sides see genuine benefits in putting an end to the rancour that has blighted relations ever since the 2016 referendum, especially at a time when a war is raging on the European continent.
Outside the Guildhall, Eurosceptic Conservative MPs and Ulster unionist politicians took stock of the agreement and Sunak knows he has a big job at home to persuade his critics that now is the time for compromise with Brussels, not further confrontation.
Boris Johnson, the former prime minister, who in recent days has advocated a more belligerent approach to the EU, still has his supporters. But Sunak’s allies said the vast majority of Tory MPs “just want to get this done”.
One EU diplomat said: “Finally we’re dealing with a PM that’s ready to engage constructively and take responsibility to solve real problems for the people and businesses in the UK and Northern Ireland in particular.
“It opens up the prospect of a wider normalisation of the EU-UK relationship, which is quite timely given the state of the world.”
Britain and the EU have already teamed up on sanctions against Russia over its full-scale invasion of Ukraine.
But Sunak’s Brexit deal with the EU over the so-called Northern Ireland protocol opens up the prospect of tangible economic gains for the UK: an obvious priority for a prime minister grappling with a cost of living crisis ahead of a general election expected next year.
It removes the danger of trade retaliation by the EU if Sunak’s government had proceeded with legislation to unilaterally rewrite the protocol, something the UK could have ill-afforded given the looming recession.
A further bonus is the proposed readmission of the UK into the EU’s €95bn Horizon science programme, a move that will confer benefits both to UK researchers and those in the bloc.
Joël Reland, a research associate at the UK in a Changing Europe think-tank, said there were wider gains in prospect, if the two sides agree. These include deeper co-operation on energy policy, and the possibility that the UK and the EU could extend grace periods permitting tariff-free trade in electric vehicles.
“This is quite a significant moment,” said Reland. “For the first time since 2016 a UK government is putting the economic consequences of Brexit before the politics . . . It unlocks opportunities to enhance trade elsewhere.”
A more ambitious agenda, parts of which would probably go beyond the appetite of Sunak’s government, could entail efforts to reduce constraints on cross-border mobility of workers.
Other potential options on the menu are the mutual recognition of EU and UK safety and quality assurance marks and professional qualifications, and striking a veterinary deal to ease border checks on food.
The Labour party has already said it expects to pursue some of these options if it wins the election. Sir Keir Starmer, Labour leader, gave his full support to Sunak’s deal with the EU.
“Frankly, any steps in this direction are going to be an improvement on what we have got,” said Starmer. “I can say with confidence we back the deal.”
A more immediate benefit would be to open the door to an improvement in UK-US relations.
US president Joe Biden had been pressing the UK to reach a deal with the EU on the Northern Ireland protocol ever since taking office in 2021. An agreement should pave the way to a restoration of devolved government in Northern Ireland.
“I commend UK and EU leaders upon reaching this important agreement. It is now vital that all parties return to the NI assembly,” Brendan Boyle, a Democratic member of the House of Representatives from Pennsylvania, said on Twitter.
The deal will enhance the prospect of Biden attending events in Belfast in April marking the 25th anniversary of the Good Friday Agreement that ended decades of conflict in Northern Ireland.
It might also facilitate work by Joe Kennedy III, US special envoy to Northern Ireland for economic affairs, to foster more American investment in the region.
Sunak has delayed a parliamentary vote on his Brexit deal for the time being to give MPs “time and space” to digest the Windsor framework. Eurosceptic Tories will take their lead from their allies in Northern Ireland’s Democratic Unionist party, who last year forced the collapse of the region’s government in protest at the protocol.
But Sunak’s hopes of selling the deal were given a boost when senior Eurosceptic Conservative MP Jacob Rees-Mogg said the UK prime minister had “done very well” in negotiations with Brussels.
Meanwhile, Steve Baker, the Northern Ireland minister who once called himself the “hard man of Brexit”, scotched suggestions that he might quit Sunak’s government, saying: “I can only say this. The PM is on the cusp of securing a really great deal for everyone involved.”
Two key tests for Sunak’s deal lie ahead. The first will involve the DUP’s 12 party officers studying the legal text before deciding whether the party should end its boycott of the assembly at Stormont.
The second test focuses on the European Research Group of pro-Brexit Conservative MPs assembling a “star chamber” of lawyers to also pore over the text before deciding how to respond.
Trouble could still be in the offing. But pro-Europe Tories claim that the ERG is no longer the potent force it once was, with one saying that fewer than 30 Tory MPs turned up to a meeting of the group last week to discuss Sunak’s deal.
“Rishi would probably gain an advantage in taking them on: it would prove he isn’t weak,” said one former Tory minister.
Another ex-minister added: “This is a moment of celebration for the government. Rishi has achieved at the very least more than Theresa May, Boris Johnson, Liz Truss and David Cameron combined.”