Lord David Frost, the Secretary of State for Brexit Affairs, called on Brussels to “keep calm and maintain balance” if the United Kingdom continues to threaten to suspend part of the Northern Ireland Brexit agreement.

The United Kingdom is seeking to rewrite the agreement for Northern Ireland to leave the region in the EU’s single commodity market to prevent the restoration of the North-South trade border on the island of Ireland.

For several months, the two sides have been in a standoff over post-Brexit trade rules in the region. The United Kingdom threatened to trigger Article 16. If the two sides believe that the arrangement has caused “serious economic and social problems”, either party can use the guarantee. Terms or circumstances are difficult” or “trade diversion”.

After the fruitless conversation last week Maros Sefcovic, the EU’s Brexit negotiator, warned that if the UK implements its threat, it will face “serious consequences.” These measures may include more intensive customs and health checks to slow down cross-channel trade, and even terminate trade and cooperation agreements that allow duty-free and quota-free trade between the EU and the UK.

Sevkovic met with the EU ambassador in Brussels on Wednesday to discuss possible retaliatory measures if Article 16 is triggered. The two sides will hold the fourth round of talks on Friday.

In a speech in the House of Lords on Wednesday, Frost said that if negotiations fail, triggering Article 16 to suspend certain parts of the so-called Northern Ireland agreement is the UK’s “only option”.

He stated that Brussels had suggested that the UK could only take this action at the cost of “large and disproportionate retaliation.” He added: “I gently advise our European friends to stay calm and proceed in proportion.

“They may remind themselves that in the Belfast Agreement, no government or country cares more about the stability and security of Northern Ireland than we do.”

Frost has stated since July that due to the economic and political chaos caused by the agreement, it has reached the threshold of rationality for using Article 16.

But Frost’s tone was significantly softened, insisting that the two sides are still negotiating, and hinted that the United Kingdom is still several weeks away from unilaterally suspending some of the agreements.

“There is still a real opportunity to get rid of confrontation, overcome current difficulties, and establish a new and better balance,” Frost told his colleagues.

He added: “There is more to be done, and I certainly will not give up the process unless and until it is very clear that there is nothing to do. Of course we have not been there yet. But if we reach that in due course Point, Article 16 safeguard measures will be our only choice.”

In issuing a warning to the EU, he continued: “If the EU chooses to react in a disproportionate manner and decides to exacerbate rather than reduce the problems in Northern Ireland, it is of course their business.”

His speech was delivered by four senior Democratic congressmen in Washington Issue a joint statement It warned that the British threat of triggering Article 16 was “dangerous”.

“The British threat to invoke Article 16 of the Northern Ireland Protocol not only threatens to destabilize trade relations, but also threatens the hard-won peace. We call on the UK to abandon this dangerous path and commit to fully implement the Northern Ireland Protocol,” they said.