Sammy Wilson, the DUP’s Brexit spokesman has accused the head of Northern Ireland’s civil service of being “politically motivated” after he warned against no-deal Brexit.
David Sterling had warned of grave, profound and long-lasting consequences of no-deal on Northern Ireland.
Speaking during a parliamentary committee on Northern Ireland, Mr Wilson said: "I have no doubt this was written for a political motive."
When the letter arose in conversation again, an animated Mr Wilson said: "We've got from David Sterling in his letter, it's a scare tactic."
When Lady Hermon, a member of the committee, interrupted, Mr Wilson said: "I don't care if he's head of civil service or Santa Claus, it really doesn't matter, the fact of the matter is, he's got it wrong."
Mr Wilson also suggested that Northern Ireland business leaders had been briefed on the withdrawal agreement before it was seen by MPs in the House of Commons.
He said: “I think that maybe they were given a precis of what was in the agreement, designed to play down bad parts of it, and emphasise the parts that would be attractive to them.
"One thing I do know is that they made their pronouncements before the 587-page document was available, they must have made it on a basis of a briefing they were given, no one should do that especially when one party has an interest that it's skewed in a certain way."
The DUP MP said that he found it “odd” that any businesses in Northern Ireland would support the agreement.
He added: "Let's just take the Ulster Farmers Union, if they had read the agreement they would actually find that state aid rules applying to Northern Ireland would mean that the EU could cap that support, in accordance with what they saw as the appropriate policy.
"As far as businesses, I do find it very difficult to understand why Northern Ireland businesses who export around the world would wish to be excluded from UK trade deals in the future."