Deal announced by Prime Minister Rishi Sunak and European Commission president Ursula von der Leyen follows more than a year of tense negotiations over the "Northern Ireland Protocol".
Britain and the European Union have reached an agreement on the crucial overhaul of trade rules in Northern Ireland, a breakthrough aimed at resetting seriously strained relations since Brexit.
Prime Minister Rishi Sunak and European Commission president Ursula von der Leyen adopted the deal at talks in Windsor, west of London, both sides announced on Monday.
"I believe the Windsor Framework marks a turning point for the people of Northern Ireland," Sunak said, adding that Britain's parliament would get a vote on a new agreement his government has reached with the European Union to amend post-Brexit trade rules for Northern Ireland.
"Parliament will have a vote at the appropriate time and that vote will be respected," he told reporters at the news conference.
Von der Leyen also praised the agreement saying it would allow "a stronger EU-UK relationship standing as close partners, shoulder to shoulder now and in the future".
Their meeting followed more than a year of tense negotiations over the "Northern Ireland Protocol", which has unsettled the province 25 years on from a historic peace deal that ended three decades of armed conflict.
Agreed in 2020 as part of Britain's EU divorce, the pact kept the province in the European single market for physical goods and subject to different customs rules than the rest of the UK, angering pro-UK unionists there and eurosceptics in London.
The UK government had threatened a unilateral overhaul of the protocol unless the EU agreed to wholesale changes, souring diplomatic ties and risking a wider trade war, but that prospect now appears to be receding.
"I'm looking forward to turning a page and opening a new chapter with our partner and friend," von der Leyen said as she left Brussels ahead of the talks.
The new deal will work for all, she said, adding that the Windsor framework "respects and protects our respective markets".
A group representing all the main industries in Northern Ireland said the new deal will help secure the stability and certainty that impacted businesses had sought.
"Reaching an agreement is an important step in securing the stability and certainty businesses have been seeking," said the Northern Ireland Business Brexit Working Group, whose members include manufacturers, retailers, farmers and hauliers.
The EU chief was also set to meet King Charles III while in Windsor, stoking accusations in the UK that Sunak was trying to project royal endorsement of the deal.
It is likely to face opposition from Brexiteers, including Sunak's potentially rebellious predecessor Boris Johnson, and from lawmakers representing the pro-British unionist community in Northern Ireland.
Sunak's spokesman insisted the monarch's meeting with von der Leyen was decided by Buckingham Palace.
The agreement ends a long chapter of talks between London and Brussels, under the direction of three different British prime ministers and the cloud of the war in Ukraine.
It is seen as long overdue to help stabilise both Northern Ireland and the wider UK's post-Brexit relationship with its European partners.
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