Officials from Britain and the European Union are meeting on Wednesday to try and defuse a row over Northern Ireland that threatens to spill over into this week’s Group of Seven summit.

European Commission Vice President Maros Sefcovic is holding talks with the U.K.’s Brexit minister, David Frost, in an effort to resolve the trade dispute—part of which now revolves around whether British will be allowed to ship sausages to Northern Ireland. Frost will then head to Cornwall, England, to support Prime Minister Boris Johnson, who is set to come under pressure from U.S. President Joe Biden and EU leaders.

At issue is whether Johnson is backsliding from a legally binding agreement he made less than two years ago to secure the U.K.’s orderly withdrawal from the bloc: in a bid to avoid customs checks on the island of Ireland, Johnson agreed to put a trade border in the Irish Sea. As a result, goods reaching Northern Ireland from the U.K. now have to comply with a different set of health and safety checks stipulated by the EU.

The U.K. government says it underestimated the disruption its decision would wreak on trade between Great Britain and Northern Ireland. With supplies of food and medicines to the province roiled, it has attacked the EU for being legalistic and inflexible, and sought to delay implementing parts of the accord. The bloc has threatened retaliation if Britain continues in this way.

“Expectations are very low that there will be a resolution,” said David Henig, director of the U.K. Trade Policy Project at the European Centre for International Political Economy, a think tank. “There’s a lot of gloom about.”

Johnson is due to hold discussions with Biden and EU leaders on the sidelines of the summit in Cornwall, England, and Frost’s presence suggests that Johnson is preparing to mount a stiff defense of his position if necessary. The Times newspaper reported this week that Biden will warn Johnson not to renege on the deal, while several senior U.S. politicians have previously said that Britain can forget a trade if the Brexit pact is broken.

”We are also ready to use the various means available to us to protect our interests and to ensure the integrity of the interior market, to make sure that agreements are respected and to also protect the Good Friday Agreement,” EU Council President Charles Michel told European lawmakers on Wednesday morning, referring to the 1998 peace deal that largely brought an end to the troubles. “We repeat our solidarity with Ireland.”

Tensions between London and Brussels are set to grow in coming days. A grace period allowing traders in the rest of the U.K. to continue selling certain goods in Northern Ireland is set to expire on June 30. After that, some processed meat products such as sausages will be banned from sale because the EU rules have no provision for certifying that they are safe to eat.

The British government has hinted it could again intervene unilaterally to extend it.

“There’s no case whatsoever for preventing chilled meats from being sold in Northern Ireland,” Johnson’s spokesman, Max Blain, told reporters on Tuesday. “We will consider all our options.”

Sefcovic said on Tuesday the EU will act swiftly to ensure Britain respects its obligations in international law, putting the two sides on a fresh collision course if the issue isn’t resolved.

Under the terms of the wider Brexit deal, both sides have the right to impose retaliatory tariffs in extreme circumstances. The EU could also prevent the U.K. financial services industry getting access to the single market.

Risk of Violence

The most likely outcome of Wednesday’s meeting is neither breakthrough nor breakdown, according to Henig. Both sides, he said, will agree to continue working on the problems surrounding the protocol. “I’m not sure either side has a really good idea of how to unblock this,” he added.

One step that would, at a stroke, remove the need for most checks on food entering Northern Ireland would be a veterinary agreement between the U.K. and EU, under which Britain would agree to follow the bloc’s plant and animal health rules. Yet the British government has so far resisted the idea because it would limit its regulatory autonomy.

As the political impasse continues, the threat of upheaval and protest in Northern Ireland grows. Johnson’s border has become a flashpoint for pro-British unionists opposed to any degree of separation from the rest of the U.K.

Reg Empey, a former leader of the Ulster Unionist Party, was involved in negotiating the Good Friday Agreement which largely ended three decades of conflict in Northern Ireland. He blames the protocol for reducing the availability of food in the province, raising costs for business and delays in approving critical drugs.

If Britain and the EU can’t fix these problems, further protests are likely as Northern Ireland’s protestant communities prepare to hold their marches in coming weeks, he said in an interview.

“Things become unpredictable and uncontrollable,” Empey said. “There is the potential for additional public protests and the consequences that flow from that.”