The British government on Monday introduced a bill to Parliament on amendments to the post-Brexit rules that govern trade with Northern Ireland.  

The European Union says it will respond with all measures at its disposal if Britain pushes ahead with unilateral changes to the Brexit deal on Northern Ireland. It has said any changes would breach international law. Following the announcement, the EU warned that it could launch "infringement procedures" against the UK.

Earlier in the day, UK Foreign Secretary Liz Truss said London wanted a "negotiated solution" to the issue with Brussels and denied that the move was illegal. The UK government had remained quiet about the details of its plan but said they will be "lawful and correct."

Johnson himself said the changes would help ease pro-British unionist concerns over the Brexit deal.

US Secretary of State Antony Blinken urged the UK to continue "good-faith negotiations" with the EU in a call with Liz Truss later on Monday, the US State Department said.

What changes have been mentioned?

The proposed changes include the setting up of a "green channel" for goods moving from Britain to Northern Ireland that are destined to stay in the UK.

Goods being sent further to the EU would be directed to a "red channel." The UK government has promised penalties for those who try to abuse the system and take advantage of the EU's single market from the UK.

They are expected to eliminate European Union state aid rules on subsidies provided to businesses by public authorities in the province.

UK government ministers have also previously said that they wish to no longer allow the European Court of Justice to be the sole arbiter of any disputes, arguing that British courts should have some role.

How did the EU respond to the introduction of the bill?

"It is with significant concern that we take note of today's decision by the UK government to table legislation disapplying core elements of the Protocol," European Commission Vice-President Maros Sefcovic said in a statement. "Unilateral action is damaging to mutual trust."

Sefcovic insisted that the EU will not renegotiate the post-Brexit trade agreement, calling it "unrealistic."

"No workable alternative solution has been found to this delicate, long-negotiated balance. Any renegotiation would simply bring further legal uncertainty for people and businesses in Northern Ireland," he said.

He added that the commission may continue legal procedures against the UK that it had put on hold in September 2021, as well as launching new procedures, in the face of the unilateral move from London.

Ahead of the announcement, Irish Foreign Minister Simon Coveney said the changes marked "a particular low point in the UK's approach to Brexit."

"The UK's unilateral approach is not in the best interest of Northern Ireland. Far from fixing problems, this legislation will create a whole new set of uncertainties and damage."

"Britain has taken a very regrettable decision that goes against all the agreements between the EU and Britain," German Chancellor Olaf Scholz said.

"It is also unjustified because the European Commission made many pragmatic proposals," he added. "The EU will be unified in its reaction and it has the full range of instruments at its disposal."

What is the Northern Ireland Protocol?

The protocol is part of the UK's Brexit deal with the EU. It lays out a system of rules which governs trade in Northern Ireland since the UK left the EU. It was devised as a means of avoiding a hard border on the island of Ireland, allowing Northern Ireland to remain in the EU's single market.

Ireland's open border, and the rights of people on either side of it to seek whichever citizenship they prefer and to move freely between the two sides, were core components of the 1998 Good Friday peace accord.

The protocol instead effectively places a trade border in the Irish Sea, between Northern Ireland and the rest of the UK. Pro-British communities in Northern Ireland say the trade checks erode their connection to Britain.

Northern Ireland show the highest economic growth outside London in the third quarter of last year, according to figures released last month. However, the UK government says the implementation of the protocol that it agreed with Brussels has damaged trade between the province and the rest of the United Kingdom. 

A day before the new legislation was unveiled, the head of Irish nationalist Sinn Fein party, Mary Lou McDonald, accused UK Prime Minister Boris Johnson's government of choosing a "destructive path."

Sinn Fein won a historic victory in the Northern Ireland Assembly, however, the pro-British Democratic Unionist Party (DUP) has so far refused to form a power-sharing government in Belfast as long as the current post-Brexit trade agreement remains in place.

ab, rc/msh (Reuters, AFP, dpa)