The DUP leader briefed the European Research Group (ERG) at Westminster on Tuesday night, following on from his talks last week with Prime Minister Rishi Sunak.

Sir Jeffrey said that Brussels needed to accept that goods traded within NI were subject to UK laws and standards, and not those of the EU, if there was to be an agreement his party could support.

However, the said: “It is possible given the level of progress that has been made and the principles that have already, I’m told, been agreed, the outstanding issues could be resolved within the next few days.”

He added: “I think lines have been crossed. Therefore, that suggests to me there is the potential to resolve this issue.

"We can’t have a situation where business in Northern Ireland are able to bring goods in from Great Britain and sell them as UK standard products, and make the same product themselves in Northern Ireland but they are required to make them to EU standards. That is not acceptable.”

In a separate development, prominent Brexiteer Jacob Rees-Mogg accused the prime minister of imitating Theresa May's doomed Brexit strategy as Tory Eurosceptics were urged to allow the "time and space" needed to fix the protocol difficulties.

On his ConservativeHome podcast, Mr Rees-Mogg said: "There seems to me to be no point in agreeing a deal that does not restore power-sharing [at Stormont].

"That must be the objective. If it doesn't achieve that objective, I don't understand why the government is spending political capital on something that won't ultimately succeed."

He said the Bill has the support of "the person who had a mandate from the British voters" – Boris Johnson – and he said Mr Sunak should first get the approval of the ERG.

"I don't know why so much political capital has been spent on something without getting the DUP and the ERG onside first," Mr Rees-Mogg said.

DUP leader meets with ERG on how a NI Protocol solution could be easily reached, as Rees-Mogg fires warning