The UK will have to safeguard its position “in other ways” if it is not able to reach an agreement with the EU over the Northern Ireland Protocol, according to the UK’s Brexit negotiator.

Lord Frost had said there was “momentum” for his Government to “secure a solution based on consensus” following a meeting in Brussels with European Commission vice-president Maros Sefcovic on Friday.

Writing in the Mail on Sunday, Lord Frost said: “The current problems with the protocol go to the heart of our territorial integrity, of what it means to be one country and one market. They will not just disappear.

“I still hope the EU can show the ambition needed to fix the problem by agreement. If they can’t, of course we will have to safeguard our position in other ways.”

It comes hours after campaigners gathered at the border between Northern Ireland and the Republic to warn the UK Government against triggering Article 16.

A crowd gathered at Carrickcarnon on Saturday to demand that the post-Brexit arrangements introduced for Northern Ireland are retained and protected.

Speculation has continued for months that the UK Government is preparing to trigger Article 16, which would suspend elements of the post-Brexit arrangements in place in Northern Ireland.

The Northern Ireland Protocol has been fiercely opposed by unionists and loyalists, who object to the creation of a trade barrier with Great Britain.