Henry Newman is Director of Open Europe.

By the start of next week, we will know whether the EU is likely to agree that Britain has made “sufficient progress” in the Brexit negotiations to start talking about trade and its future outside of, but alongside, the EU. The final decision will be made in the room at the European Council meeting, but (as is the way of these things) the conclusions will be drafted in advance.

On the first of the three ‘withdrawal issues’, citizens’ rights, only technical details remain to be resolved. Regarding the second, money, the Prime Minister has reportedly made a new contingent commitment for the UK to pay a proportion of the EU’s total liabilities. The final issue – Northern Ireland/Ireland – remains as yet unresolved and Brussels is suggesting that it has the potential to delay progress in the negotiations. If that happens, the chance of reaching any sort of deal will fall dramatically.

As I have argued previously, the EU’s decision to separate out these three issues from the wider talks about Britain and the EU’s future is regrettable and wrong. There is no requirement in EU law to arrange the talks in this phased way. Brussels repeatedly seeks to claim that its “sufficient progress” test is a technical assessment of the level of the talks, which must be passed on all three issues, but it is in fact a political judgement. I was told by senior diplomats of a major member state that they insisted on the EU using the term “sufficient progress” precisely because it was not an exact test.

On Northern Ireland/Ireland it’s particularly difficult for the UK to demonstrate that it’s made progress so far. While it has committed to protecting the Belfast Agreement, the UK Government has long argued, perfectly reasonably, that it’s hard to make commitments now about the border without knowing what sort of trade or customs relationship we will have in the future. But they have promised that they want to avoid a hard border and published a position paper outlining various policy options to avoid physical infrastructure at the frontier. These have been dismissed as ‘magical thinking’ by the EU. Meanwhile, Ireland has ramped up the pressure and is playing hardball. Tony Connelly, the RTE journalist, says that his discussions “reveal a carefully co-ordinated escalation by Ireland and the [EU’s Brexit] Task Force”.

Clearly Brexit does create some serious problems for Ireland, as Paul Goodman outlined in his article on Sunday. It’s perfectly legitimate for Ireland to seek to defend its interests in these negotiations and indeed, since the Anglo-Irish Agreement, the UK has recognised that Ireland has a legitimate interest in the Province as well. There are also domestic motivations: the new Irish Prime Minister is leading a minority government and is facing an unfolding political crisis which could force him to early elections. And the Irish are also well aware that this is their moment of maximum leverage in the negotiations. If they green light trade talks now it will be much harder unilaterally to force concessions later.

Although the Peace Process was not exactly an EU success story, it is now intertwined with EU law. There are complex North-South questions to resolve and cross-border issues such as energy and power networks. It is unavoidable that the border between the Province and Republic will become an external frontier of the EU. The question is not whether there is a border but whether it is a hard-physical border with barriers or a light-touch border with intelligence-led checks conducted away from the frontier. On the movement of people, there is strong political will to maintain the free movement of Irish and British nationals via the Common Travel Area (which after all predates the EU, and already includes a non-EU territory – the Isle of Man). Goods are – somewhat ironically – proving more complicated than people.

Ireland rightly recognises that the return of a hard border, even for goods, could endanger the peace process. Yet rather than working with the UK to pressure Brussels to avoid the need for such a border, the Irish Government has called for either the whole of the UK, or Northern Ireland alone, to remain in the Customs Union. It’s worth noting that – contra recent calls by the Labour Party and by a small number of Tory MPs for the UK to stay in the Customs Union – no non-EU member other than Monaco is in the EU’s Customs Union. Even members of the European Economic Area such as Norway, Lichtenstein, and Iceland are outside the Customs Union. Turkey has a partial Customs Union with the EU’s Customs Union but the effect of this, as Open Europe argued in our Nothing to Declare paper, is that Turkey cannot sign independent trade deals or vary its external tariffs, yet is not automatically included in the EU’s third-party deals. It makes no sense for the UK to remain in the Customs Union after Brexit.

Ireland has reportedly gone even further. Tony Connelly has suggested that the price of sufficient progress for the Irish would be a “form of words” on how the UK would avoid a border which “should reflect no regulatory divergence on either side of the border”. Although Irish sources have suggested to me that this report was over-written, some within the Irish political establishment are clearly demanding that post-Brexit the UK cannot ever diverge from the rules governing the Single Market or the Customs Union.

The danger seems to me that the Irish are creating impossible conditions for the UK. If sufficient progress is denied in December, because the UK (rightly) refuses to commit to being a permanent rule taker from the EU, the domestic pressure for Theresa May to abandon the talks entirely could quickly become unsurmountable. Equally, the message which Irish diplomats in London are seeking to promote, namely that the UK will have no stronger ally or closer friend during the second phase of the talks, will certainly be drowned out. Relations could seriously break down between the two neighbours. The EU may argue that the impact of “no deal” would be worse on the UK than the EU27, but Ireland would take the biggest hit of any EU member, and that would guarantee a hard border.

But there is a path through. Yesterday the former Taoiseach, Bertie Ahern, spoke out with words of wisdom. He endorsed the UK view that technology could ameliorate the border, and correctly suggested that the EU may have to turn a “blind eye” to certain movements of items. For its part, the UK has already accepted that maintaining the Common Travel Area will mean that EU nationals can enter Great Britain by crossing the Irish border. The key point is that Britain and Ireland have forged a path through their troubled history with a political commitment to work together. A shared determination to trust one another and to find a solution to the complexities of Brexit is urgently needed.