Post-Brexit tensions have crystalized into a worsening fight over Northern Ireland, the only part of the U.K. to share a land border with an EU country, which is Ireland, the Associated Press reported. Under the most delicate and contentious part of the Brexit deal, Northern Ireland remains inside the EU’s single market for trade in goods, in order to avoid a hard border with EU member Ireland. That means customs and border checks must be conducted on some goods going to Northern Ireland from the rest of the U.K., despite the fact they are part of the same country. The regulations are intended to prevent goods from Britain entering the EU’s tariff-free single market while keeping an open border on the island of Ireland — a key pillar of Northern Ireland’s peace process. The U.K. government soon complained the arrangements weren’t working, saying the rules impose burdensome red tape on businesses. Never short of a belligerent metaphor, 2021 has already brought a “sausage war,” with Britain asking the EU to drop a ban on processed British meat products such as sausages entering Northern Ireland. Northern Ireland’s British Unionist community, meanwhile, says the Brexit deal undermines the 1998 Good Friday peace accord — which sought to protect the rights of both Unionist and Irish Nationalist communities — by weakening Northern Ireland’s ties with the rest of the U.K. The bloc has agreed to look at changes to the Protocol, and is due to present proposals on Wednesday. Before that move, Britain raised the stakes again, with Britain’s Brexit minister David Frost demanding sweeping changes to the way the agreement is governed. In his speech in the Portuguese capital, Frost said the Protocol “is not working.” “It has completely lost consent in one community in Northern Ireland,” he said. “It is not doing the thing it was set up to do – protect the Belfast (Good Friday) Agreement. In fact it is doing the opposite. It has to change.” Most contentiously, he said the EU must also remove the European Court of Justice as the ultimate arbiter of disputes concerning trade in Northern Ireland and instead agree to international arbitration. He said the role of the EU court “means the EU can make laws which apply in Northern Ireland without any kind of democratic scrutiny or discussion.” Read more.