Triggering the Northern Ireland Protocol’s Article 16 remains a “very real option”, Lord Frost has said.

The UK’s lead Brexit negotiator said he would like to see a deal agreed with the European Union, but if that is not possible Article 16 is a “legitimate option”.

Article 16 is a safeguard mechanism within the protocol which, when triggered, can effectively suspend elements of the arrangements.

Lord Frost is in Northern Ireland for a series of meetings with political parties and businesses as the negotiations with the EU remain ongoing.

He met the DUP and UUP on Tuesday night, and is set to meet the other parties on Wednesday.

DUP leader Sir Jeffrey Donaldson said he wants to see progress “within a reasonable time” or he expects the Government to take decisive action, such as the triggering of Article 16.

Lord Frost said he would “very much hope” to bring the talks with the EU to a conclusion.

“That’s what we would most like to do. If we can’t, if there can’t be an agreement, then obviously the famous Article 16 is a very real option for us,” he told BBC Radio Ulster.

Asked about Irish Foreign Affairs minister Simon Coveney’s assessment that there will be a deal before Christmas, Lord Frost said: “I would like to progress this as fast as we possibly can, I’m glad there’s ambition on the EU side … I think it can be done.

“Whether it will be done is a different question, it’s got to be a deal that deals with the problems, solves the underlying problems and makes a difference to businesses and people’s lives.”

Lord Frost declined to talk about the “detailed negotiating position” in the talks with the EU but described the question of how goods move from Great Britain and Northern Ireland as “at the heart of it”.

“We have said that we don’t see any reason why goods that everyone acknowledges are going to stay in Northern Ireland need to go through processes,” he said.

“Obviously if they go on into Ireland we have said that we will police them in accordance with EU law, that’s perfectly reasonable, but goods staying in Northern Ireland – why do they need to go through a customs check?”

Lord Frost said there is a “gap” between the UK and EU positions.

“We are in a situation where the EU have made some proposals, at the moment without going into detail, I’m not sure they would solve these problems of checks and processes for goods moving into Northern Ireland, but we keep talking and we’re seeing if we can move this forward in a way that does produce consensus,” he said.

Challenged on triggering Article 16, Lord Frost responded: “I think Article 16 is a legitimate option within the treaty. Article 16 is an article in the protocol, it’s a safeguard mechanism and its use is perfectly legitimate, that’s why it is there in the protocol and that’s why it is an option in this process.

“I think it’s everyone’s preference, it’s certainly our preference to try to resolve it without using Article 16, but if we can’t resolve it in the negotiations, Article 16 is a perfectly legitimate option to solve these problems. That’s why it has to be on the table.

“It’s obviously a matter for the European Union if they were to choose to retaliate against any use of Article 16, which I repeat is perfectly legitimate.

“I don’t think it helps if they chose to (retaliate). If we use Article 16, it’s about making trade flow more freely within the United Kingdom, and I don’t see why it would help for the response to that from the European Union to be sanctions, retaliation and making trade more difficult. I don’t understand why that would help the situation here, and I hope everybody can stand back from that.”

Unionists and loyalists in Northern Ireland have been strongly opposed to the protocol, regarding it as a border in the Irish Sea, straining the union between the region with the rest of the UK.

Lord Frost said Northern Ireland’s place in the union is “strong”.

“This Government is not neutral on that question. I think there is no doubt that the trade diversion that has occurred and the way the protocol is working has worried people about the strength of the connections and that’s playing into the sense of economic and social concern that we pick up, and it’s our wish to resolve that as consensually and reasonably as we possibly can,” he said.