Northern Ireland unionists attack EU-exit treaty

If nothing was done, they would launch a judicial review of the Brexit deal, they warned, in what would amount to a series of court challenges in Belfast and London on whether it violated the British constitution.

"Neither the Northern Ireland assembly, the Northern Ireland executive, nor the people of Northern Ireland consented to the protocol being put in place or the flow of goods from Great Britain to Northern Ireland being impeded by checks," the DUP leader, Arlene Foster, said.

The 'Northern Ireland protocol' was part of the Brexit deal, which kept Northern Ireland in the EU customs union, creating a trade border in the Irish Sea.

It did so to maintain an open land border between Ireland and Northern Ireland, in line with the Belfast agreement, a 1998 treaty that ended decades of sectarian violence.

The British constitution is a set of laws, such as the 1800 Act of Union and 1998 Northern Ireland Act.

And for the DUP, the Brexit deal went against it all.

"Fundamental to the Act of Union is unfettered trade throughout the UK ... yet the Northern Ireland protocol has driven a coach and horses through both the Act of Union and the Belfast agreement," Foster also said.

The UUP said the same day it would "explore every political and legal avenue to get the Northern Ireland protocol annulled".

The smaller Traditional Unionist Voice partly joined them, as did a handful of former pro-Brexit MEPs and opposition party MPs in England.

The British parliament is to hold an emergency debate on the subject on Monday.

A special 'UK-EU joint committee' is also meeting on Wednesday to try to get trade flowing.

The EU aggravated Irish tensions earlier this year, when it invoked the protocol to try to block coronavirus vaccine exports to the UK in a dispute with pharmaceutical companies.

It reversed the move, but not before a British outcry which saw UK cabinet minister Michael Gove promise to reinvent the Northern Ireland arrangements.

And for his part, David Trimble, a former UUP leader, also turned up the heat on Saturday.

"I personally feel betrayed by this [the Northern Ireland protocol]," Trimble, who helped negotiate the 1998 peace deal, said in The Irish Times newspaper.

It had already caused "unintended but unquestionably escalating tensions" which endangered lives, he said.

"There is real potential for those who have engaged in past violence to take action again into their own hands," Trimble added, referring to former paramilitary forces.

But the Irish taoiseach, Micheál Martin, played down the post-Brexit trade disruption as "teething problems" in remarks to French media.

Another risk - that Ireland might seek reunification with Northern Ireland in a referendum, aggravating sectarian tension - was also unrealistic, Martin told the France 24 broadcaster on Sunday.

"I don't foresee a border poll certainly over the next number of years, not during the lifetime of this government," he said.

And the Northern Irish nationalist party, the Social Democratic and Labour Party (SDLP), agreed.

"The DUP's legal action against the Ireland protocol is ill judged and will only further entrench the febrile political environment," the SDLP's Colum Eastwood said on Sunday.

"The [Northern Ireland] protocol ... prevents a hard border in Ireland and guarantees dual market access for local businesses", Eastwood said.