In this file photo dated Nov 7, 2022, European Commission President Ursula von der Leyen (left), and British Prime Minister Rishi Sunak meet during the COP27 climate summit in Sharm el-Sheikh, Egypt. (PHOTO / AP)

LONDON — Prime Minister of the United Kingdom (UK) Rishi Sunak is to meet President of the European Commission Ursula von der Leyen in the UK on Monday over post-Brexit deals, a joint statement said on Sunday.

Von der Leyen and Sunak "agreed to continue their work in person towards shared, practical solutions for the range of complex challenges around the Protocol on Ireland and Northern Ireland," the statement said.

Under the protocol, Northern Ireland is part of British customs territory but is subject to the EU's customs code

A dispute over the Northern Ireland Protocol -- the rules governing post-Brexit trading arrangements for Northern Ireland -- has strained Britain's relations with the European Union (EU).

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Under the protocol, Northern Ireland is part of British customs territory but is subject to the EU's customs code, value-added tax rules and single market rules for goods.

However, a de facto Irish Sea border was thus created between the British mainland and Northern Ireland, meaning goods transported to and from Northern Ireland are subject to border controls.

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Northern Ireland's pro-Brexit Democratic Unionist Party has demanded the removal or replacement of the protocol as a precondition for it to sit in the assembly and form a devolved government.