BORIS Johnson has claimed his plan to override parts of the Northern Ireland Protocol is “not a big deal” despite its potential to spark a trade war with the EU.

The Prime Minister said the proposed changes were a “relatively trivial set of adjustments in the grand scheme of things” ahead of legislation being published later today.

Critics, including some Tory MPs, have warned that unilaterally rewriting parts of the post-Brexit trade arrangements for Northern Ireland could breach international law.

The UK Government, which previously said it was ready to break the law “in a limited way”, now says its plan will comply with it, but the EU remains highly sceptical.

Ireland’s Foreign Affairs Minister Simon Coveney has said the plan would “ratchet up” tension and breach the UK’s international commitments.

But Mr Johnson today said the legislation would introduce “relatively simple” bureaucratic changes and warned it would be a “gross overreaction” if Brussels sought to retaliate by triggering a trade war.

The UK’s plans are also key to the return of a power-sharing executive in Northern Ireland.

The protocol is seen by Northern Ireland Unionists as a threat to the UK, as it aligns the province with EU rules, with a trade border in the North Sea between NI and Great Britain.

The DUP has refused to enter a powersharing executive with Sinn Fein unless the protocol is substantially rewritten or scrapped.

The legislation will give ministers powers to override elements of the protocol, which was jointly agreed by Mr Johnson’s Government and the EU 

It currently requires regulatory checks and customs declarations on goods moving between Great Britain and Northern Ireland, because they could flow through the open border with Ireland into the EU’s single market.

The new Northern Ireland Protocol Bill will see the Government reduce the checks on the movement of goods across the Irish Sea, with a possible “green lane” to fast-track goods staying in Northern Ireland, and another for those moving onwards into Ireland and the EU. 

It could also see businesses in Northern Ireland given the ability to choose whether to follow UK or EU regulations, depending on who they are trading with.

Mr Johnson told LBC Radio: “What we have to respect - this is the crucial thing - is the balance and the symmetry of the Belfast/Good Friday Agreement.

“We have to understand there are two traditions in Northern Ireland, broadly two ways of looking at the border issues. One community at the moment feels very, very estranged from the way things are operating and very alienated.

“We have just got to fix that. It is relatively simple to do it, it’s a bureaucratic change that needs to be made.

“Frankly, it’s a relatively trivial set of adjustments in the grand scheme of things.”

Mr Johnson disagreed with claims that the move breaks international law, arguing that “our higher and prior legal commitment as a country is the Belfast/Good Friday Agreement and to the balance and stability of that agreement”.

Foreign Secretary Liz Truss briefed Mr Coveney about the legislation in a call this morning.

A spokesman for Mr Coveney said he told Ms Truss that “publishing legislation that would breach the UK’s commitments under international law, the Brexit Withdrawal Agreement and Northern Ireland Protocol is deeply damaging to relationships on these islands and between the UK and EU”.

The plan marked a “particular low point in the UK’s approach to Brexit, especially as Ms Truss has not engaged with negotiations with the EU in any meaningful way since February”, the spokesman said.

Mr Coveney also used a Twitter post to suggest the UK was seeking to “deliberately ratchet up tension with an EU seeking compromise”.

As well as her talks with Mr Coveney, Ms Truss also spoke to European Commission vice-president Maros Sefcovic about the UK Government’s action.

In a sign of the UK’s frustration at Brussels’ stance, she said: “Our preference is a negotiated solution, but the EU must be willing to change the protocol itself.”

UK Government sources said Ms Truss was not “picking a fight” with the EU but was focused on preserving the Belfast/Good Friday Agreement and Brussels’ refusal to alter the protocol meant unilateral action was required.

Sir Keir Starmer has said Labour MPs will vote against the Bill, which may also be opposed by Tory rebels unhappy with Mr Johnson’s leadership.

Sir Keir said: “I think the answer to this is to accept there are some problems in the way the protocol works but they can be resolved around the negotiating table with statecraft, with guile, with trust. Unfortunately, we don’t have those in the current Prime Minister.

“They won’t be resolved with legislation that breaches international law and that, frankly, will impede the negotiations that, in the end, will be needed to settle this.

“So the Government is going down the wrong track here.”