The UK and the European Union sealed a deal on Monday to resolve their thorny post-Brexit trade dispute over Northern Ireland, hailing the agreement as the start of a “new chapter” in their often fractious relationship.

Iran PressEurope: Northern Ireland is the only part of the U.K. that shares a 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.

British Prime Minister Rishi Sunak and European Commission President Ursula von der Leyen announced the grandly titled "Windsor Framework" after agreeing to the final details in Windsor, near London.

Von der Leyen told a news conference it was "historic what we have achieved today." Sunak said there had been a "decisive breakthrough."

The agreement, which will allow goods to flow freely to Northern Ireland from the rest of the UK, ends a dispute that has soured UK-EU relations, sparked the collapse of the Belfast-based regional government and shaken Northern Ireland’s decades-old peace process.

Fixing it ends a long-running irritant for von der Leyen and is a big victory for Sunak — but not the end of his troubles. Selling the deal to his own Conservative Party and its Northern Irish allies may be a tougher struggle. Now Sunak awaits the judgment of Northern Ireland’s Democratic Unionist Party, which is boycotting the region’s power-sharing government until the trade arrangements are changed to its satisfaction. 219