CARBIS BAY (BLOOMBERG) - Prime Minister Boris Johnson clashed with European Union leaders, warning the UK could suspend parts of the Brexit agreement if a dispute over trade rules for goods shipped to Northern Ireland is not resolved.

Johnson said on Saturday (June 12) that Britain could act unilaterally unless the bloc agrees to a compromise when the current grace period governing trade in the region expires on June 30.

If a pragmatic solution to facilitate the flow of goods is not found, then the UK will do "whatever it takes," Johnson said.

"I think if the protocol continues to be applied in this way, then we will obviously not hesitate to invoke Article 16," Johnson told Sky News on the sidelines of the Group of Seven (G-7) summit he is hosting this weekend.

"I've talked to some of our friends here today, who do seem to misunderstand that the UK is a single country, a single territory," Johnson said. "I just need to get that into their heads."

The argument is at risk of overshadowing Johnson's carefully laid plans for the first in-person gathering of the leaders of the seven major economies since the pandemic began. The British leader wants the summit to focus on action to tackle the coronavirus crisis in the developing world and concrete steps to tackle climate change.

The escalation follows a series of what were clearly some tense meetings with his European counterparts, with time running out to resolve the matter. EU officials confirmed there was strong disagreement behind closed doors. Those have now spilled out in the open.

Veiled threats

For its part, the EU has threatened to retaliate if the British government breaks the terms of the accord. It remains to be seen if Johnson will follow through, and how far each side is willing to push the war of words.

"I would really hope that a UK-EU trade war would not take place and I really think that with all the opportunities there are for dialogue I would be surprised if we ended up with a UK-EU trade war," World Trade Organisation director-general Ngozi Okonjo-Iweala told reporters on the sidelines of the G-7.

"It is too costly for both sides; this is not what the world needs right now."

One EU official briefed on the discussions said that while a pragmatic solution will need to be found, it would be wrong for the UK to assume that the 27-nation bloc will simply forget about the protocol. Another EU official said the rhetoric needed to be toned down and that members states are aligned.

Article 16 is an emergency trigger that allows either side to intervene and suspend parts of the deal if the protocol's application creates "serious economic, societal or environmental difficulties."

Under the terms of the Brexit accord, Northern Ireland - unlike the rest of the UK - remained under the EU's customs and single market rules to avoid creating a visible border with the Irish Republic, a move that would risk reviving sectarian conflicts.

"I certainly think that the protocol is capable of being used and interpreted - by the way, up to the EU - in a pragmatic way or a theologically draconian way," Johnson said in a separate interview with Channel 5.

"I don't happen to think that a trade war is a very sensible or likely way forward. I just think that we need some pragmatic solutions."

The question, as host, is how far he wants let Brexit hijack a summit he had hoped would showcase British leadership and present a positive image of the country as a global trading nation after successfully concluding its split from the EU.

Johnson has faced repeated questions over the fallout from Brexit and pressure from US President Joe Biden's team over the specific pressures on Northern Ireland.

During his meeting with Johnson, French President Emmanuel Macron strongly told the British leader he must honor the divorce deal he signed with the bloc, and hoped a reset of souring relations between the two sides would follow, according to an official.

Bloody-minded

Even as the French and British sides were meeting, UK Foreign Secretary Dominic Raab stepped up his rhetoric against the bloc. The choice over whether the argument worsens is one for the Europeans, Raab told BBC radio on Saturday.

"They can be more pragmatic about the implementation of the Northern Ireland protocol in a way that is win-win or they can be bloody-minded and purist about it, in which case I am afraid we will not allow the integrity of the UK to be threatened," he said.

In the six months since the UK completed its divorce from the EU, relations between the two sides have deteriorated, with a series of arguments over unrelated issues, including vaccine sharing, supermarket supplies, and fishing rights for French boats in British waters.

The latest flashpoint is over rules affecting the movement of goods into Northern Ireland. Under the terms of the Brexit divorce agreement, a trade border was created in the Irish sea, roiling supermarket supply chains and stirring violent protests among Northern Ireland's pro-UK supporters.

Tensions between the UK and EU have been rising for months, with the British criticising the bloc's "legal purism" and calling for more flexibility.

Back in January, the EU nearly triggered an emergency clause in the Brexit accords as it rushed out a mechanism to restrict vaccine exports with little consultation. Key officials were barely consulted ahead of the move, and it swiftly draw criticism across divides in Northern Ireland as well as from the Irish government.

The measure, which could have seen the reintroduction of checks on the island of Ireland in order to stop vaccines doses produced in the bloc arriving in mainland Britain via Belfast, was binned within hours of being announced - but it has since been used by the UK to justify some of its unilateral interpretations of the Brexit agreement.