The new Brexit deal marks a new start in relations with the EU after the trust vacuum of the era of Liz Truss and Boris Johnson.

Premierminister Rishi Sunak und Ursula von der Leyen, Präsidentin der Europäischen Kommission, sprachen beide von einem „neuen Kapitel“, um die Bedeutung ihrer Neufassung des Nordirland-Protokolls zu beschreiben, aber diese Worte unterschätzten den sprunghaften Wandel in den Beziehungen zwisnisen groß European Union. Officials on both sides say the decisive turning point in the talks came when they began to trust each other after years of feuding over Brexit, although the distrust was mostly on the British side.

“It shows how much you benefit from trust in European relations, not from the zero-sum games of past governments,” Michel Barnier, a former EU Brexit negotiator, tweeted on Tuesday.

The most important factor was Mr. Sunak. Despite being a staunch supporter of Brexit in the 2016 referendum, he approached negotiations with the EU differently than his predecessor, Boris Johnson.

Unlike Johnson, who resigned in September after three years as prime minister, and even Liz Truss, whose premiership lasted only 49 days, Sunak approached the challenge of the Northern Ireland Protocol as “an issue that needs to be addressed, and don’t itch.” scratched,” an EU official said.

Mr Johnson’s Northern Ireland Protocol Bill was particularly damaging as it allowed the UK to unilaterally suspend its treaty obligations. Instead of letting London negotiate, as some hard Brexiters continued to argue on Tuesday, it did just the opposite, undermining what little confidence there was and dashing hopes for peace talks.

But since taking office in October, Sunak has avoided the Brexit hype and EU jokes that have characterized Johnson’s actions, acknowledging that threats would be counterproductive and that constructive dialogue would bring results. “Of course you have a line of prime ministers,” a senior British official acknowledged on Tuesday. “The Sunak government itself is not directly responsible for the law, and I think that has created little political space.”

In temperament and character, Mr. Sunak is very different from Mr. Johnson. His style is much closer to that of Frau von der Leyen, and last October he quickly changed to show her that he wants to turn the page on the bombast of the Johnson and Truss eras.

In particular, he sought a workable solution for the Northern Ireland Protocol and urged his negotiators to work calmly with their counterparts in the Commission to reach an agreement. This secrecy also suited the technocratic commission (indeed, the EU ambassadors were only informed of the details during the press conference of Mr. Sunak and Ms. von der Leyen on Monday).

This was all a welcome change for Ms von der Leyen and her team, but seeing Mr Johnson fail again and again, they still needed proof that the UK could be sure it was holding your word.

A data-sharing agreement signed in early January, giving the EU real-time access to UK intellectual property trade data systems, helped build confidence. This also applied to the consultations proposed by the EU on its energy package late last year. During the negotiations on the Protocol, the UK immediately recognized that the EU Court of Justice would be the final arbiter on internal market issues. And the vaunted “Storont brake” announced in the package has already been canceled as an “emergency brake” or veto: while a “last resort” mechanism allows the UK to agree to updated EU legislation in Northern Ireland. the block, in turn, would be challenged by the Commission.

But the main reason for the negotiations was the simple fact that both sides were willing to work together in good faith. With all the changes in the legal text of the Northern Ireland Protocol, dialogue is perhaps the most important part of the new Windsor structure. “It’s also the depth and breadth of these new consultation arrangements … that provide a solid foundation for constructive momentum,” a UK insider said.