Boris Johnson is being warned against triggering Article 16 of the Northern Ireland Protocol to suspend parts of post-Brexit arrangements for the Irish border.
There is growing speculation that the prime minister could soon trigger Article 16 as ongoing talks between the EU and UK continue to fail to resolve problems such as the “sausage war” and other issues.
Sky News revealed last month how ministers are holding discussions inside a key cabinet committee about the repercussions of such a move.
However, Mr Johnson has been given fresh warnings about the impact of invoking Article 16.
Sinn Fein president Mary Lou McDonald said the activation of Article 16 by the UK could put at risk the entire Brexit withdrawal deal.
“It would demonstrate just again colossal bad faith and demonstrate again that Ireland, the north of Ireland in particular, is collateral damage in the Tory Brexit as they play games and play a game of chicken with the European institutions,” she told BBC One Northern Ireland’s Sunday Politics programme.
“I would also say that if the British government imagine that they hold all of the cards they are wrong, and they’re playing a very, very dangerous game, up to and including perhaps jeopardising the entire withdrawal agreement.”
Ms McDonald called on the UK government to “act in good faith” and “adopt a position that is serious and that has a long-term view” as she warned of “very grave” consequences.
Meanwhile, Labour leader Sir Keir Starmer said that suspending parts of the Northern Ireland Protocol would not solve the UK-EU dispute.
“I don’t think that triggering Article 16 will resolve the dispute in relation to the protocol in Northern Ireland,” he told the BBC’s Andrew Marr Show.
“That isn’t in the interests of the communities in Northern Ireland or businesses in Northern Ireland. What is in their interests is resolving the issues.
“Because of the way the protocol was drafted, because of what the Prime Minister signed, it is perfectly true that there are checks from Great Britain to Northern Ireland – we want to reduce those.”
Sir Keir added: “What I am saying is don’t rip up the protocol because that has that very important central purpose, which is to protect the no border in Northern Ireland.”
The Labour leader also suggested that Mr Johnson was “constantly trying to pick a fight on things like this, so he hopes people don’t look elsewhere in the forest, which are things like the Owen Paterson affair”.
The Northern Ireland Protocol was agreed between the UK and EU as a means of avoiding a hard border on the island of Ireland, and is a key part of the UK’s divorce deal with the EU.
However, the prime minister has said the current implementation of the protocol – which keeps Northern Ireland within much of the EU’s single market and customs rules – is having a “damaging impact” on the people of Northern Ireland.
One flashpoint includes a possible ban on chilled meats – such as sausages – moving from Great Britain to Northern Ireland.
The oversight role of the European Court of Justice in the operation of the Protocol also remains a key sticking point in UK-EU talks.
Brexit minister Lord Frost is due to meet again with European Commission vice-president Maros Sefcovic in London next week.
Following talks between the pair in Brussels on Friday, the UK government said that “progress had been limited” but that “gaps could still be bridged through further intensive discussions”.
Prior to Friday’s meeting with Mr Sefcovic, Lord Frost said: “We’re not going to trigger Article 16 today, but Article 16 is very much on the table and has been since July.”