British Prime Minister Rishi Sunak has struck a new deal on post-Brexit trade rules for Northern Ireland with European Union president Ursula von der Leyen. 

Amendments to the Northern Ireland Protocol seek to resolve tensions caused by the 2020 post-Brexit arrangements governing Northern Ireland, which is part of the UK but operates with an open border with the Republic of Ireland, an EU member.

The protocol allows goods to be smoothly transported across the border between Northern Ireland and the Republic of Ireland without checks but, in doing so, created a customs border of sorts between mainland UK and Northern Ireland.

A year ago, Northern Ireland's devolved government effectively shut down after the Democratic Unionist Party (DUP) withdrew in protest over the protocol and has not fully functioned since.

Throughout the terms of three British prime ministers, the UK and EU have been negotiating a solution to the stalemate.

"We may have had our differences in the past, but we are allies, trading partners and friends," Mr Sunak said.

Mr Sunak announced three major "steps forward" in what has been dubbed the Windsor framework:

• New 'lanes' for goods trade. Goods destined for Northern Ireland are to be processed through a 'green lane', which will have a reduced requirement for customs. Goods destined elsewhere on the island will go through a 'red lane' and be subject to EU checks.
• Recognises Northern Ireland as part of UK. Mr Sunak says "quintessentially British" products will once again be available in Northern Ireland, including trees and seeds in garden centres and any medicines approved by UK medical regulators will be available in Northern Irish pharmacies and hospitals
• Retains 'safeguards' of sovereignty. While other EU laws still apply in Northern Ireland, a new safeguard, called the Stormont brake allows the Northern Ireland Assembly a say over EU laws and can stop them from applying.

The amendments place Northern Ireland in a unique compromise where the trade of goods comes under UK regulations, but other EU laws can still apply.

"We all collectively share an ambition to avoid a hard border between Northern Ireland and the Republic, and that's why there's a role for EU law in Northern Ireland," Mr Sunak said.

Ms von der Leyen said she felt a "great sense of satisfaction" in coming to the agreement and was confident the deal would "work for all".

When asked why the current UK PM had been able to negotiate change the protocol when his predecessor Boris Johnson could not, Ms von der Leyen said Mr Sunak brought a "very constructive attitude" to the table.

It remains to be seen, though, whether it will go far enough to end political deadlock in Northern Ireland and satisfy critics in Britain and the Republic.

Northern Ireland is the only jurisdiction of the UK which shares a land border with the EU.

Striking a deal — that preserved the peace, protected the EU's single market and avoided new borders on the island and with Britain — has been a major challenge for the UK Government.

Northern Ireland minister in the UK Government, Steve Baker, said he was on board with the deal.

"I am delighted, hand-on-heart glad to accept the whole thing," he said.

Politicians in the UK and Northern Ireland are now reviewing the agreement, a process Mr Sunak and Ms von der Leyen accept "will take time".

The DUP has stressed it would not be pushed into a "hasty decision" on the agreement.

Why is trade in Northern Ireland difficult?

As Mr Sunak put it today, Northern Ireland's borders exist as a "delicate balance" because the 1998 Good Friday Agreement is central to it.

The Good Friday Agreement is a treaty negotiated to end decades of conflict called 'the Troubles' that arose after Ireland was partitioned in the 1920's between those who wanted a united Ireland, and those who supported the partition and British rule.

It acknowledges Northern Ireland's constitutional status as part of the UK, rather than the Republic of Ireland, but also allows for a referendum to unite the island if a majority of people in both jurisdictions vote for it.

A power-sharing assembly was set up, establishing a local government at Stormont that requires the participation of parties from both Northern Ireland and the Republic of Ireland.

Overall, Northern Ireland has enjoyed peace for much of the 25 years since the agreement was signed, with only a small number of splinter groups involved in sporadic attacks.

Britain's departure from the European Union created a problem for Northern Ireland by raising the prospect of a "hard border" with its EU-member neighbour.

For nationalists, any imposition of border checks would contravene one of the agreement's core tenets of fostering north-south cooperation.

The Northern Ireland protocol that was implemented by Boris Johnson effectively left Northern Ireland in the EU goods market and created a customs border between Northern Ireland and the rest of the UK.

Pro-British communities in Northern Ireland said Mr Johnson's protocol erodes their place within the UK.

Mr Sunak said the new framework protects the "aspirations and identity" of all people in Northern Ireland, but it remains to be seen if the DUP agrees.

ABC/Reuters