Northern Ireland Secretary Karen Bradley has made clear a no-deal Brexit will deliver customs and regulatory checks on the island of Ireland.
She stressed that, while the UK Government is committed to working to avoid a hard border, World Trade Organisation (WTO) rules are "very clear" and checks would need to be carried out on consignments passing between two customs territories on a contemporaneous basis.
The Conservative MP also suggested that UK and EU commitments outlined in last December's joint report on maintaining the Common Travel Area - an agreement which allows free movement for UK and Irish citizens in Britain and Ireland - would also be thrown into doubt in a no-deal scenario.
Ms Bradley, who pitched the merits of the draft Brexit deal to business leaders in Belfast on Monday, said the report's undertakings to protect the Single Electricity Market (SEM) and ensure certain citizens' rights are upheld post-Brexit would also fall by the wayside if the UK crashes out.
"They are agreed as part of the withdrawal agreement, that is not something that is agreed in a no-deal situation," she said.
During the business briefing, Ms Bradley was asked to react to comments from Taoiseach Leo Varadkar that a border would be inevitable in a no-deal scenario.
The Secretary of State was challenged on the apparent contrast between Mr Varadkar's statement and the UK Government's oft-stated position that it is committed to ensuring no hard border post-Brexit.
In response, she urged the audience to familiarise themselves with WTO rules on the need for checks to happen.
After the event, she elaborated: "WTO rules means that there has to be a requirement that checks are carried out, that tariffs are paid, that customs declarations have to be completed - now, how that is done will be matter for us to negotiate and consider, but the fact is the WTO is very clear that if there is two separate customs territories, checks have to be able to be carried out on a contemporaneous basis on consignments passing between the two customs territories.
"We will do, as the UK Government, everything we can to avoid there being a hard border on the island of Ireland - we do not want to see there being physical infrastructure at the border and we will try to facilitate that in any way we can.
"But the WTO rules are clear - tariffs will apply, checks will be required - that is what the WTO says."
Despite the DUP's trenchant opposition to the Government's plan, Ms Bradley did not mention the name of the party once during her appearance at Belfast Met College - not in her speech, during a question-and-answer session with business leaders or a later press conference.
Despite being pressed, she repeatedly insisted that she did not want to "single out" one political party, instead urging all MPs to get behind the deal.
She insisted the draft agreement protects the "precious Union" of Great Britain and Northern Ireland and warned it is the only option on the table.
"Be under no illusion - the EU won't start negotiations all over again," she said.