The government has been forced to deny that a measure it quietly adopted this week effectively kills off the chances of a “no deal” Brexit and locks the UK into a tight customs arrangement with the EU.
Ministers were also quick to deny that the amendment – passed without a vote – rules out the possibility of the UK adopting the future customs arrangements preferred by Brexiteers.
But both Tory and Labour MPs now say the little debated measure, making illegal any “physical infrastructure, including border posts, or checks and controls”, is the most significant thing to have occurred in this week’s fraught commons Brexit debates.
It comes amid a growing concern among pro-Brexit Conservative MPs that the government is slowly moving towards a deal involving something looking very similar to the existing EU customs union.
The Independent was among the few organisations to cover the move by the government to simply accept a plan passed by the Lords that enshrines in law the commitment to have no infrastructure at the Irish border.
With excitement focussing on the row over parliament’s role in Brexit, it was only on Wednesday that MPs started to point out the importance of the Irish border amendment.
Ex Tory-chancellor Ken Clarke said: “It was the most significant thing that happened yesterday.”
He went on: “The legally binding commitment yesterday extends the needs of the Irish border to the whole of the United Kingdom.
“So we’re talking about Dover, and we’re not having a border down the Irish Sea, so the United Kingdom has got to negotiate an arrangement with the EU as a whole, which has no new frontier barriers.
“So effectively we are going to reproduce the customs union and the single market – and the government will not be able to comply with Tuesday’s legal obligation unless it does so.”
Tory MP Heidi Allen agreed, saying: “It’s huge, it actually says, I think, logically we will have to come to a customs union agreement, partnership, love dance, don’t care what you call it, that’s what we will need to avoid any border to Northern Ireland.”
Former Tory attorney general Dominic Grieve, who has led much of the technical debate on the government’s approach to Brexit, added: “Not only will we have to stay in a form of customs arrangement amounting to a union, but we’re also going to have to have a high level of regulatory alignment because otherwise the life that takes place along the border will be impossible because of different regulations on either side.”
The government is still trying to formulate what kind of customs arrangements to seek in EU negotiations but the main option preferred by Brexiteers and Brexit Secretary David Davis is the so-called maximum facilitation or “max fac” option.
It would see new technology used to deal with cross-border trade, reducing the need for border checks.
But Labour’s shadow Brexit secretary Sir Keir Starmer said: “If maximum facilitation does involve infrastructure checks or controls, it would be unlawful under the provision passed yesterday, therefore it cannot happen.
“The only answer to no hard border in Northern Ireland in the end is a customs union and high levels of market alignment, the fact that was accepted by the government and turned into domestic law gives it a status it didn’t have until yesterday.”
When Labour MP Chuka Umunna challenged Conservative minister Robert Buckland over whether the amendment now meant a “no deal” Brexit is “inconsistent with Government policy”, he said “I entirely agree”.
The comment seemed to fly in the face of Theresa May’s promise that “no deal, is better than a bad deal”, but a source from Mr Davis’s Department for Leaving the European Union, said it did not because Ms May has always also said that she is not aiming for a “no deal” situation.
The source also denied that the amendment itself committed the UK to a kind of customs union, pointing out that the government has said it will keep the border open, even if it means keeping it free of infrastructure on the UK side.
They also argued that the government’s proposal for a maximum facilitation customs arrangement, would not mean infrastructure at the border itself but elsewhere, and so it also would not be ruled out by the amendment.
An official DExEU spokesperson said: “We have made clear our commitment to avoiding a hard border between Northern Ireland and Ireland, as well as avoiding any borders within our United Kingdom.
“The Lords amendment only relates to how we use some of the powers in the EU (Withdrawal) Bill and does not have any wider effect. We are confident that we will secure a deal which works for the UK and the EU, including Ireland.”