Ireland’s government met on Tuesday to discuss contingency planning in the event of a European Union trade war with the United Kingdom, according to deputy prime minister Leo Varadkar.

London and Brussels are currently at odds over the implementation of post-Brexit trading arrangements for Northern Ireland, which London claims are unworkable.

The two sides are in talks to try to resolve the dispute, with the EU warning of “serious consequences” if the UK suspends the trading protocol unilaterally.

“We’re preparing,” said Varadkar, who was credited with persuading UK Prime Minister Boris Johnson to agree to a Brexit deal with the EU as prime minister in 2019. “We had a meeting of the Cabinet sub-committee on Brexit yesterday (Monday), essentially to dust down and restart our contingency preparations should we get into difficulty,” he told RTE radio.

No one wants the EU to halt the larger trade deal with the UK, but if London invokes the protocol’s Article 16 suspension clause, Brussels may have “no choice” but to implement “balancing measures,” he said.

“I sincerely hope Britain does not go down this road,” Varadkar added, warning that it would “potentially undo” the Brexit deal and be bad for the UK, Northern Ireland, and Ireland. The Democratic Unionists, Northern Ireland’s largest pro-UK party, said the UK was correct to plan to invoke Article 16, but a trade war would benefit no one.

According to Jeffrey Donaldson, his meeting on Monday with UK Brexit minister David Frost “certainly suggested that from the UK’s perspective, there’s still a couple of weeks left in these negotiations.”

However, he downplayed the chances of success unless the EU came up with “firmer” and “more realistic” proposals.

“I believe that a positive outcome in terms of an agreed solution is unlikely,” he added. “In those circumstances, I expect the UK government to take unilateral action to address the difficulties created by the Northern Ireland Protocol.”

Frost, who said last week that time was “running out” for talks and that Article 16 was “very much on the table,” is scheduled to meet with European Commission Vice-President Maros Sefcovic in London on Friday.

The EU has proposed a slew of changes to the protocol, including eliminating checks on most goods heading to Northern Ireland from the rest of the United Kingdom (England, Scotland, and Wales). However, the UK’s insistence on appointing an international arbiter to replace the European Court of Justice to resolve disputes is a step too far for Brussels.

The protocol effectively kept the British-run province, which shares the United Kingdom’s only land border with the EU, in the European customs union and single market.

Checkpoints were put in place to prevent goods from entering the EU through the back door via member state Ireland.

However, unionist parties in Northern Ireland are opposed to the agreement, claiming it jeopardizes the province’s place in the UK, and there has been unrest from hardliners.

In the last two weeks, two buses have been set on fire in unionist areas of Northern Ireland. In late October, a Queen’s University Belfast poll found that 52 percent of Northern Ireland respondents thought the protocol was a “good thing,” compared to 48 percent who thought it was a “bad thing.”

Complicating matters is the need to keep the border between Northern Ireland and Ireland open – a key tenet of the 1998 peace agreement that ended decades of conflict over British rule – which neither side wants to jeopardize.

The UK-EU relationship has been strained further by a separate dispute with Paris, which is dissatisfied with the number of licenses London has granted to French trawlers to fish in British waters.