Britain and the European Union have agreed to revise post-Brexit trade rules for Northern Ireland. The issue had been a major thorn in the relationship between Britain and the EU.

Northern Ireland is part of the UK, but shares a land border with EU member Ireland. Even after Britain left the bloc, Northern Ireland was required under a protocol to follow some EU rules. This was to ensure a free flow of goods between Northern Ireland and Ireland.

But the arrangement meant that customs checks and complex paperwork are required for goods headed to Northern Ireland from the rest of the UK, creating major bottlenecks in distribution.

Under the deal announced on Monday, checks and paperwork will be drastically simplified for goods destined to remain in Northern Ireland, by setting up a separate "green lane" for screening.

British Prime Minister Rishi Sunak welcomed the agreement, telling reporters that it "delivers smooth-flowing trade within the whole United Kingdom."

European Commission President Ursula von der Leyen said the deal "provides for long-lasting solutions that both of us are confident will work for all people and businesses in Northern Ireland."

The EU had raised strong objections when Britain's previous administration tried to unilaterally change part of the protocol. The latest agreement is expected to bring an end to the standoff.