Sammy Wilson has been told he shouldn't be surprised that the Port of Larne had been told to prepare to become a border control point - as it was a direct result of Brexit which he had been a "cheerleader" for.
The DUP MP told Boris Johnson in the House of Commons on Wednesday that he had "in my hand a letter received by the management of the Port of Larne only this week stating that they have to prepare to become a border control post and 14 acres has been looked at for car parking or for lorry parking and for construction".
He added: "Can he explain how Northern Ireland can remain a full part of the United Kingdom if people coming from the rest of the UK into Northern Ireland have to pass through a border control post and would he advise the management to tear this letter up as well?"
Mr Johnson replied: "I haven't seen the letter he describes but I can tell him absolutely, categorically that there will be no new customs infrastructure for the very simple reason that under the protocol it is absolutely clear in black and white that Northern Ireland is part of the customs territory of the whole of the United Kingdom and will be joining the whole of the United Kingdom in our new independent trade policy and doing free trade deals around the world."
The Port of Larne declined to comment.
But SDLP Brexit spokesman Matthew O'Toole MLA said Mr Wilson had "jumped the shark a long time ago".
"He cheered Brexit, empowered English nationalist extremists and voted down a deal which would have avoided the checks he now fulminates about," he said.
"If he is annoyed about Brexit's consequences, he can write a letter to himself complaining about Sammy Wilson facilitating it. He owns this and he should apologise for it."
Ulster Unionist MLA John Stewart said: "It's not so very long ago that Sammy Wilson was a cheerleader for Brexit, merrily slapping down any voices cautioning that there might be consequences for the Union itself. It now appears that the penny has finally dropped, and that Sammy has realised that under the very Brexit policy he sold to the people of Northern Ireland as the future there will be a border control post in his own constituency at the port of Larne.
"In effect the border has moved from Newry to Larne. It may only have just dawned on Sammy Wilson now, but he certainly can't say he wasn't warned."
Alliance MP Stephen Farry said the news "should be no surprise to the DUP".
"New border control post infrastructure was always going to be part of the protocol and was confirmed by the UK Government in its recent command paper. This situation is entirely of the DUP's own making," he said.
"They campaigned for Brexit, opposed a soft Brexit, and opposed the backstop, which didn't require this level of checks. Alliance will do all we can to mitigate the impact of the protocol but we have no illusions of the scale of the challenge or how we got here."
Sinn Fein MP Chris Hazzard said: "Unique protections have been secured in the Irish Protocol to protect the Good Friday Agreement and the all-Ireland economy and to avoid any hardening of the border on the island of Ireland.
"These protections must be maintained and implemented. The British Government must not be allowed to resile from or renege on the commitments and legal obligations it has entered into."
Meanwhile, the Government has said it will not make changes to the protocol in the withdrawal agreement after it emerged that the European Commission had requested amendments.
The withdrawal agreement, which took the UK out of the European Union in January, committed the UK and Brussels to establishing a joint committee to oversee and monitor the application of the treaty.
But MPs have accused the UK Government of not being upfront about what amendments it was accepting during the regular meet-ups, warning ministers that "significant improvements" were required in terms of accountability to Parliament.
A report from the Commons European Scrutiny Committee, published on Wednesday, pointed out that on May 15 the European Commission published a proposal to amend the withdrawal agreement to address a number of "errors and omissions".
The changes included "certain adjustments to the number and scope of EU laws on goods that will continue to be applicable in Northern Ireland beyond the end of the post-Brexit transition period", as per the protocol affecting the region in the withdrawal agreement.
Under the agreed exit plan, Northern Ireland will continue to follow a number of EU rules in sectors such as agriculture in order to avoid a hard Irish border, an issue the joint committee is designed to monitor.
At a joint committee meeting with Brussels officials on June 12, ministers did not ratify the proposed alterations affecting Northern Ireland but did accept other changes, the report stated.
In response a Government spokeswoman said: "We are committed to working transparently with Parliament as it scrutinises the work of the withdrawal agreement joint committee. We have received the European Scrutiny Committee's report and will respond formally in due course.
"With regard to proposed amendments to the Northern Ireland Protocol, we have been clear that we are not seeking to reopen or renegotiate the protocol.
"As we have set out in our Approach to the Protocol published last month, it must be implemented in a way that upholds the Belfast (Good Friday) Agreement, preserves NI's place in the UK, and respects the unique circumstances of Northern Ireland. As such, we support flexibilities that work for NI businesses and which minimise the impact of the protocol on the everyday life of communities."