The British government’s plan to take unilateral action and change the post-Brexit deal sparks anger and threats from the European Union.

UK foreign secretary Liz Truss has proposed legislation in parliament that would change one of the most sensitive elements of the Brexit agreement that handles how goods move in and out of Northern Ireland, known as the Northern Ireland Protocol.

Truss claims the relationship between Great Britain and Northern Ireland has been “undermined” by the Northern Ireland Protocol.

The European Commission, the EU’s executive arm, has threatened to retaliate with “all measures at its disposal” if the UK Conservative government goes ahead and changed the rules of the Protocol.

The EU argues the Brexit Withdrawal Agreement is a legally binding international treaty that has been ratified and went into effect on January 31, 2020.

Germany has expressed outrage that the UK was taking unilateral action to change the treaty at a time when the West is accusing Russia of breaking international law. 

Germany’s envoy to the EU, Sebastian Fischer, wrote on social media “let’s just all threaten each other with breaking international law. Makes for really good partnerships.”

Maros Sefcovic, the European Commission’s Vice-President issued a statement saying a “stable relationship with the United Kingdom must be based on the full respect of the legally binding commitments that the two sides have made to one another, based on the implementation of the [Brexit] Withdrawal Agreement and the Trade and Cooperation Agreement [TCA]. Both parties negotiated, agreed, and ratified these agreements.”

Sefcovic highlighted that the Northern Ireland protocol was chosen by the UK following “long and intensive discussions” to reach a Brexit deal. 

He also noted the “protocol is an integral part” of the “international agreement signed by the EU and the UK.” 

Sefcovic warned that “unilateral actions contradicting an international agreement are not acceptable.”

“Should the UK decide to move ahead with a bill disapplying constitutive elements of the Protocol as announced today by the UK government, the EU will need to respond with all measures at its disposal,” he added. 

Other critics of Boris Johnson's government say violating the Brexit deal would pose risks to a united European front in response to the Ukraine war and could further damage the British economy amid record levels of inflation.

The main opposition Labour Party MP Stephen Doughty insisted that “this is not a time for posturing or high-stakes brinksmanship, the prime minister negotiated this deal, signed it, ran an election campaign on it. He must take responsibility for it and make it work.”

Even a Conservative member of parliament, Simon Hoare, admitted the government move would break international law saying “respect for the rule of law... runs deep in our Tory veins, I find it extraordinary that a Tory government needs to be reminded of that.”

Experts say the EU could retaliate by triggering clauses in the TCA that would terminate the entire Brexit trade agreement, spelling the end of tariff-free trade in both directions along with all the other elements of the deal,

This will leave the UK in a no-deal Brexit scenario, serious measure analysts argue, with long-term consequences for future ties between the UK and the 27-member bloc.

The EU could also implement retaliatory measures more quickly by suspending only the trade aspects of the TCA, leaving other Brexit deal areas intact.

As stipulated in the TCA this allows the EU to “suspend, in whole or in part”, access to its waters. Analysts argue the EU would only have to give seven days’ notice which means a trade war could be triggered within a week.

Observers point out that for the EU to be considering any retaliation just 18 months after the two parties sided ways with an international agreement reflects how the West can negotiate in bad faith. 

The timing of the British government’s decision is not coincidental as it comes on the backdrop of elections in Northern Ireland which was won by the Nationalist Party Sinn Fein.

The stunning victory, the first in Northern Ireland’s history, saw a party that advocates for the reunification with the Republic of Ireland come out on top amid growing popularity. 

After Brexit, England, Scotland, and Wales (all connected by land) left the European single market. However, sending goods to and from Northern Ireland requires additional checks.

Unionists in Northern Ireland are opposed to this as they believe it creates a border in the Irish Sea and threatens Northern Ireland’s place in the United Kingdom. 

Northern Ireland is the only region of the UK that has a land border with the European Union, namely the Republic of Ireland which is not part of the UK. 

The Northern Ireland Protocol prevented the creation of a physical border between the Republic of Ireland and Northern Ireland as any physical barriers could have been the target of armed fighters and bring back unrest to the region. 

To avoid the physical border and checks on the island of Ireland, the UK and EU drew up the Northern Ireland protocol, which moved the trade border to the Irish Sea.

The Democratic Unionist Party (DUP), labels the protocol as an "an existential threat" to the future of Northern Ireland. 

In the Northern Ireland Assembly election earlier this month, the DUP refused to return to a power-sharing deal with Sinn Fein. 

Under the rules of the Northern Ireland Assembly, there must be a power-sharing executive with both a First and Deputy First Minister who represent both Unionist and Nationalist communities.

The DUP refused to nominate one, citing the Northern Ireland Protocol.

The DUP welcomed the decision by Truss, saying that they will take “cautious” steps towards rejoining the power-sharing executive in Northern Ireland. 

Observers say the British government is taking unilateral measures on the Brexit deal to please the unionists in Northern Ireland (who want the Protocol scrapped) at the expense of legal action and a trade war with the EU. 

The DUP’s leader in Westminster, Jeffrey Donaldson, says Truss’s statement was “a welcome if overdue step.”

His party would like to see progress on the legislation “in days and weeks, not months,” he added.

Sinn Fein accuses the government of letting the DUP “hold society to ransom”.

Most other parties in Northern Ireland want to keep the protocol, with some minor changes to ease the burden on businesses.

The EU argues this was all addressed in the NI protocol saying “It avoids a hard border on the island of Ireland, protects the 1998 Good Friday (Belfast) Agreement in all its dimensions, and ensures the integrity of the EU Single Market.”

For instance, the same medicines continue to be available in Northern Ireland at the same time as in the rest of the UK, the EU commission said. 

The Irish foreign secretary, Simon Coveney, says “I deeply regret the decision of the British government to introduce legislation in the coming weeks that will unilaterally dis-apply elements of the protocol on Ireland/Northern Ireland.”

Coveney said such action was “damaging to trust and will serve only to make it more challenging to find solutions to the genuine concerns that people in Northern Ireland have about how the protocol is being implemented”.

Johnson has defended his government saying "there will be a necessity to act" over the protocol if the EU's position does not change. He said the Protocol was now out of date as it was designed before the coronavirus pandemic, a rising cost of living crisis, and Russia's war with Ukraine.