Guarantees in the Belfast Agreement have "been ripped up" by the Northern Ireland protocol, according to Democratic Unionist Party leader Jeffrey Donaldson and Traditional Unionist Voice leader Jim Allister.
Writing for The Irish Times, the pair say the consent principle of the 1998 peace deal “was central to assuring both unionists and nationalists that the future direction of Northern Ireland would be decided democratically and not by force or coercion”.
“However, the protocol has introduced seismic changes in the constitutional position of Northern Ireland,” they say.
We have no desire to see rioting in our streets, young people getting criminal records and damaging headlines across the world
Mr Donaldson was an arch-critic of the Belfast Agreement as a member of the Ulster Unionist Party, before defecting to the Democratic Unionists, while Mr Allister quit the DUP over power-sharing at Stormont.
The unionist party leaders say if safeguards in the agreement for nationalists had “been so cynically removed” then the Irish Government, the US and the EU “would have been up in arms”.
‘Frustration and fears’
“It is little wonder that there has been civic unrest in Northern Ireland as unionists fearful about the future, angry at being betrayed by their own government, being kicked around as a negotiating football by the EU and seeing all the political means of resistance blocked, seek for other ways to register their frustration and fears,” they say.
“The reason why the unrest has not spilled over into greater disorder is due to the work which we, our parties and community workers have been doing to prevent it.
“We have no desire to see rioting in our streets, young people getting criminal records and damaging headlines across the world resulting in a flight of investment from our already-damaged economy.”
Meanwhile, Fine Gael has accused Britain of a "slightly tiring" routine of regularly coming out to "trash" post-Brexit arrangements it agreed with Europe.
The party’s European affairs spokesman, Neale Richmond, insisted the Northern Ireland protocol “isn’t going anywhere”.
‘Tiring routine’
“It is a slightly tiring routine we are going through, inadvertently, every couple of weeks,” he told BBC’s Sunday Politics.
“A British government minister, usually Lord [David] Frost, will go out and trash the protocol he negotiated, be it on social media or in a newspaper, building up to a head, then we move on to this next part of the roundabout that we are on.”
Mr Richmond said the threats are “being taken seriously” by the European Commission but didn’t provide any solution.
“But I think there are solutions within the protocol,” he added.
Mr Richmond pointed to European Commission vice-president Maris Sefcovic’s and Minister for Foreign Affairs Simon Coveney’s recent visits to the North as “measures being taken” to work with “not just the political leaders but more importantly community and business leaders about the practical issues that are at hand.
“We acknowledge that they are there in relation to agri-food products, in relation to veterinary products, in relation to medicines . . . There are absolutely solutions and a will to find solutions within the protocol.”