The Brexit negotiations enter an uncertain and tricky phase in the lead-up to the December 2017 European Council (EC). If the EC fails to agree that ‘sufficient progress’ has been made on the three issues in Phase 1, discussion of the UK’s future relationship with the Union will not begin in January. The question of Ireland, and especially the border between Ireland and Northern Ireland, remains one of the most problematic issues on the agenda.

The Irish Government has clearly signalled that from its perspective, ‘sufficient progress’ has not been made on the border to merit a move to Phase 2 of the talks. This leaves the UK Government with about two weeks to satisfy EU27 – and especially Ireland – that the UK’s commitments concerning the Irish border are credible and are the outcome of serious thinking and problem-solving in London.

There are some in London who are surprised at the strength with which the Irish Government, backed by the other governments and the European institutions, has stuck to its position. That there is surprise is a surprise to us on the other side of the Irish Sea. The Irish Government, the parliament, and wider society, all understood well before the referendum result that Brexit would pose immense and distinctive challenges to Ireland North and South. Anxiety about the implications for the shared border has been to the fore because the border has only been normalised for a very short time.

The Irish border today is a wondrous achievement of the European single market and the Good Friday Agreement, which has eased and facilitated daily life. Its very ordinariness is the source of wonder, and the openness of the border is a powerful living symbol that relieves the deep tensions that characterise divided societies and contested borders. To threaten this fragile reality by the unintended consequences of Brexit is a source of palpable concern on the island of Ireland.

Faced with the June 2016 referendum outcome, the Irish Government and administration went into over-drive. Its response was multi-levelled and multi-layered, involving strands of work within Ireland (an all island Civic Dialogue), with Ireland’s EU partners and European institutions and with the British Government. The first priority was to ensure that Ireland’s partners understood that Ireland and peace on the island of Ireland was vulnerable to the contingencies of Brexit.

The objective was to align Irish interests with those of the EU. The political and diplomatic effort involved an intensive process of meetings and briefings with heads of state, foreign ministers and officials across Europe and in Brussels. By the time the UK triggered the Article 50 negotiations, Irish politicians and official had held over 400 meetings with counterparts in the other member states.

The sustained effort paid off as Ireland was identified as one of the three priority areas for the first phase of the Art.50 negotiations. Paragraph 11 of the European Council negotiating Guidelines referred to “the unique circumstances on the island of Ireland” and argued for “flexible and imaginative solutions” to issues such as the avoidance of a hard border and recognised existing bilateral agreements between the UK and Ireland, such as the Common Travel Area.

Moreover, the Irish Government succeeded in getting a European Council Declaration on Irish Unity, when the provisions of the Good Friday Agreement were written into the Council minutes. Recognition of Irish difficulties was simply the first phase of what have become tortuous negotiations.

The UK Government accepted from the outset that there were particular difficulties associated with the Irish dimension of Brexit. In her Art.50 notification letter, Theresa May referred to the UK’s unique relationship with the Republic of Ireland and said ‘We want to avoid a return to a hard border between our two countries’. This was amended in the Florence speech ‘to we will not accept any physical infrastructure at the border’.

The problem with the Irish border is not a divergence of objectives between the two sides but a well-founded concern on the part of the EU27 that their shared objective cannot be met given the UK’s preferences for its post-Brexit relationship with the EU. The decision of the UK to exit the single market and the customs union undermines the credibility of the PM’s stated objective.

Had the UK opted for an EEA-style agreement, or at the very least remained in the customs union, the problem of the Irish border would be greatly eased. However the UK’s preference for a harder rather than a softer Brexit makes it much more difficult to arrive at an agreement that will reassure Irish society and those living on the border that the bad times will not return post-Brexit.

The position of the Irish Government in the run-up to the December 2017 European Council, which is shared by the Commission’s Brexit Task Force, stems from its judgement that that position of the UK Government on the Irish border is neither credible nor compatible with its other stated aims. The UK position paper on Northern Ireland and Ireland exacerbated rather than reassured the Brexit Task Force’s unease about the fundamental tension in the UK position.

The Task Force paper on The Dialogue Ireland/Northern Ireland clearly states that ‘The onus to propose solutions which overcome the challenges created on the island of Ireland by the United Kingdom’s withdrawal from the European Union and its decision to leave the customs union and the internal market remains on the United Kingdom’.

Thus the stakes are very high both for Ireland and the UK in the next weeks. Two arguments frequently touted by UK commentators are unhelpful. The first is that the question of the Irish border is bound up in the forthcoming trade talks and as a consequence is logically part of Phase 2. This does not bear scrutiny. As the UK is intent on leaving the single market and the customs union, there is no future trade deal that will in itself avoid customs checks, inspections and controls between Ireland and Northern Ireland.

There has to be a unique deal that covers Northern Ireland. Second, is the line favoured by the Brexiteers which is that the border will be created by the EU not the UK as the latter does not want this to happen. The mendaciousness of this position is not lost on Irish society given the stated aim of ‘Taking Back Control’ but clearly not of the only land border that the UK will have with an EU state.

The Irish Government, backed by the EU, need language from the UK that essentially commits the UK to the policy consequences of its stated aim that it does not wish to have a hard border with Ireland. Speaking in Brussels on November 20, Michel Barnier said that ‘What is … unclear is what rules will apply in Northern Ireland after Brexit. And what the UK is willing to commit to, in order to avoid a hard border’.

The demand from both the Irish Government and the EU Task Force is clear; they are asking for a commitment to regulatory convergence post-Brexit for Northern Ireland. The Irish Government backed by the wider society want the UK Government and our UK neighbours to face up to the incompatibility of their stated aims concerning the border with other Brexit preferences and to live up to their responsibility as co-guarantor of the Good Friday Agreement. It has two weeks to make a credible commitment.

By Brigid Laffan, Director of the Robert Schuman Centre for Advanced Studies, European University Institute.