In politics, as in every other walk of life, it’s never a bad thing to remain calm and measured. This rule of thumb seems particularly applicable to issues around Brexit, where debate is often distorted by hyperbole and unchecked emotion.

Last week’s transition deal, like almost every previous step of the negotiation process, was greeted by excitable Brexiteers with accusations of betrayal and surrender. Less impetuous voices suggested that it represented progress towards a realistic, unhurried departure from the EU.

That serene view is probably the more appropriate reaction, but there is at least one corner of the UK where the agreement is viewed with justifiable suspicion.

Unionists in Ulster worry that the government’s fresh commitment to enact a ‘backstop’ arrangement on the Irish border is a precursor to a ‘sell-out’ that will see Northern Ireland remain in the single market, while the rest of the UK leaves. That would mean erecting a customs border between the province and Great Britain, with potentially damaging economic consequences and disastrous political symbolism.

The more benign interpretation is that the latest document, which determines that the so-called backstop should form part of the final legal text of a withdrawal agreement, simply restates the UK’s existing position.

In December’s ‘joint report’ on phase 1 of the negotiations, British negotiators agreed to maintain “full alignment” with EU rules affecting the Belfast Agreement, “the all-island economy” and “North-South cooperation”, in the absence of a trade deal or “agreed solutions” on the border.

In its ‘Draft Withdrawal Agreement’, that purported to translate the joint report into a legally enforceable document, the Commission in Brussels turned that undertaking into a commitment to accept a “common regulatory area” on the island of Ireland. Theresa May rejected this notion swiftly, saying that “no UK prime minister could ever agree to it”.

Some commentators suggest that the transition text simply means that the two parties will keep working to resolve problems around the Irish border, for now. Yet, the agreement contains significant new content, expanding the number of areas of ‘North-South cooperation’ where alignment would be necessary, if the ‘last resort’ option were applied.

The Belfast Agreement specified just five policy topics for collaboration between Northern Ireland and the Republic of Ireland. Former MEP and staunch Brexiteer, Jim Allister, points out that the transition deal adds six more: energy, telecommunications, broadcasting, justice and security, higher education and sport. A new institution, a ‘Specialised Committee’, is to be gifted with oversight powers.

While many of the provisions on Northern Ireland were coloured yellow – to signify that only broad objectives were agreed between the UK and the EU – this article was marked in green, to show that specific detail is agreed at negotiators’ level and will be revised only for technical legal reasons. It appears to undermine the government’s claim that regulatory alignment will be necessary only in a strictly limited number of areas.

Allister claims that the deal is set to “radically undermine the integrity of the UK and.. (it) will see Northern Ireland more aligned with the Republic than the UK”. Some of his concerns are shared by Lord Empey, the former Ulster Unionist leader who brokered an electoral pact with David Cameron’s Conservative Party. He believes government negotiators are demonstrating a naive approach to demands originating in Dublin, “they fail to understand the emotional and political ramifications of what we’re talking about”.

It seems there’s a vast gulf between the EU’s understanding of the “backstop” solution and the way that it’s interpreted by the UK. The key is paragraph 49 of the Joint Report, which determined that “in the absence of agreed solutions, the UK will maintain full alignment with those rules of the Internal Market and the Customs Union which, now or in the future, support North-South cooperation, the all-island economy and the protection of the 1998 Agreement”. An ongoing problem is that, while the EU has set out its aggressive interpretation, claiming that Northern Ireland must conform entirely with Single Market and Customs Union rules, Britain hasn’t properly explained how it believes the provision could be given legal effect.

In December, Northern Irish unionists took comfort from the fact that the wording of paragraph 49 suggested regulatory alignment would include the whole UK and not just Northern Ireland. However, some mainland Brexiteers are understandably unhappy at this commitment, the significance of which was immediately underplayed by the government and Brussels says that it has no business legislating for internal British arrangements, so that nuance wasn’t reflected in its legal text. It’s not unreasonable that unionist nerves are starting to jangle again.

Meanwhile, Leo Varadkar’s Dublin government tries to create fresh uncertainty around the province’s constitutional status almost daily, claiming repeatedly that it is inevitable that Britain must administer a border in the Irish Sea, if it can’t strike a trade deal with the EU and it won’t remain a Single Market and Customs Union member. The Irish prime minister now insists that an agreement on the border must be reached by October at the latest, if the backstop solution is to be avoided.

This is all taking place against a backdrop of political instability in Northern Ireland, where the devolved institutions have failed to operate since January 2017 and Brexit has become a cipher for deeper issues around nationality and identity.

The best advice is always to stay calm, but a continuing lack of clarity is creating a huge amount of anxiety, across all shades of political opinion. Surely the government must at least now explain how it believes this infamous backstop should operate, so that the more sanguine voices in Northern Ireland can start to prevail?