It was late last Christmas Eve when the European Union and Britain finally clinched a Brexit trade deal after years of wrangling, threats and missed deadlines to seal their divorce.
There was hope that now-separated Britain and the 27-nation bloc would sail their relationship toward calmer waters.
With Christmas closing in again one thing is clear — it wasn't to be.
Britain's Brexit minister on Tuesday accused the EU of wishing failure on its former member and of badmouthing the U.K. as a country that can't be trusted. David Frost said during a speech in Lisbon that the EU "doesn't always look like it wants us to succeed" or "get back to constructive working together."
He said a fundamental rewrite of the mutually agreed divorce deal was the only way to fix the exes' "fractious relationship." And he warned that Britain could push an emergency override button on the deal if it didn't get its way.
"We constantly face generalized accusations that we can't be trusted and that we aren't a reasonable international actor," Frost added — a response to EU claims that the U.K. is seeking to renege on the legally binding treaty that it negotiated and signed.
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. 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 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."
The EU is highly unlikely to agree to the change. The bloc's highest court is seen as the pinnacle of the free trade single market, and Brussels has vowed not to undermine its own order.
Ireland's Deputy Prime Minister, Leo Varadkar, said Britain's demand was "very hard to accept."
"I don't think we could ever have a situation where we had another court deciding what the rules of the single market are," he said.
Some EU observers say Britain's demand to remove the court's oversight shows it isn't serious about making the Brexit deal work.
Frost repeated the U.K.'s threat to invoke Article 16, a clause allowing either side to suspend the agreement in exceptional circumstances. That would send already testy relations into a deep chill and could lead to a trade war between Britain and the bloc — one that would hurt the U.K. economy more than its much larger neighbor.
The economically tiny but symbolically charged subject of fish, which held up a trade deal to the final minute last year, is also stoking divisions now.
France wants its EU partners to act as one if London wouldn't grant more licenses for small French fishing boats to roam close to the U.K. crown dependencies of Jersey and Guernsey, just off France's Normandy coast.
In France's parliament last week, Prime Minister Jean Castex accused Britain of reneging on its promise over fishing.
"We see in the clearest way possible that Great Britain does not respect its own signature," he said.
In a relationship where both sides often fall back on cliches about the other, Castex was harking back to the centuries-old French insult of "Perfidious Albion," a nation that can never be trusted.
Across the English Channel, U.K. Brexit supporters often depict a conniving EU, hurt by Britain's departure, doing its utmost to make Brexit less than a success by throwing up bureaucratic impediments.
"The EU and we have got into a low equilibrium, (a) somewhat fractious relationship," Frost conceded. "(It) need not always be like that, but ... it takes two to fix it."
