Rishi Sunak was pilloried by the SNP and the anti-Brexit lobby after he declared that his Northern Ireland deal would put the province in the privileged position of having access to the EU single market.

He said his post-Brexit agreement meant Northern Ireland was the world’s “most exciting economic zone” with access to both EU and UK markets.

Critics quickly pointed out that the entire UK had full access to the EU’s single market until the UK’s withdrawal, with some saying his comments showed how he does not really believe in Brexit.

On a visit to a Coca-Cola factory in Lisburn, the Prime Minister said: “Northern Ireland is in the unbelievably special position – unique position in the entire world… European continent… in having privileged access, not just to the UK home market, which is enormous… but also the European Union single market.

“Nobody else has that. No one. Only you guys: only here, and that is the prize.”

SNP Europe and EU accession spokesperson Alyn Smith MP said: “Rishi Sunak is moonlighting as a Remainer as he perfectly outlines how Scotland will be at a competitive disadvantage under Westminster control and outside the European Union.

“Northern Ireland voted to stay within the European Union and it is getting its wishes, however Scotland voted overwhelmingly to reject Brexit but we are living with the economic consequences every single day.

“Throughout the Brexit process the SNP Scottish Government made sensible suggestions so Scotland’s choice could be respected by remaining inside the single market and customs union. Those proposals were thrown in the bin and Scotland was taken along for the ride as we were dragged out of Europe against our will.

“Scotland’s economy continues to suffer the economic consequences of Brexit and they will only continue under a pro-Brexit Labour government who will keep Scotland out of the EU, no matter the economic consequences.”

Labour MP Chris Bryant tweeted: “Sunak says how wonderful it is that Northern Ireland gets privileged access to the single market. I’d like that for the rest of the UK.”

Anti-Brexit campaigner Femi Oluwole tweeted: “Rishi Sunak just spent two minutes boasting about how Northern Ireland is the “most exciting investment zone on the planet” because it has full access to the UK and EU market. You know… like we did before Brexit!”

Under the Windsor Framwork, goods destined for Northern Ireland will travel via a “green lane”, with significantly fewer checks. Anything that could cross the border into the Republic, and therefore enter the EU’s single market, will use a “red lane”.

Other changes will allow the UK government to set VAT and excise changes for Northern Ireland, rather than the EU. While some EU goods rules will remain in the province, Mr Sunak says the deal reduces the volume affected by the Brussels rulebook to less than 3%.

Under a new arrangement dubbed the “Stormont brake”, Northern Ireland politicians get the power to block any new EU rules on goods that they deem to be against its interests.

Former Brexit negotiator Lord Frost has disputed Mr Sunak’s claim that the Windsor Framework means the UK has “taken back control.”

The Conservative peer said EU law “remains supreme” and the new deal only “slightly” amends regulations so that they “bite less tightly.”

Writing in the Telegraph, he said: “That is worth having, but it isn’t taking back control. Indeed, it may entrench the protocol superstructure rather than weaken it.

“That doesn’t mean the deal shouldn’t go ahead. It will help. But it won’t remove the underlying tensions, even if the DUP does decide to go back into Stormont.”