The logic of the positions adopted by British prime minister Theresa May is there will have to be a special legal status for Northern Ireland in the agreement between the EU and UK to govern Britain's departure from the union.

This is a position endorsed by the Irish Government, as Minister for Foreign Affairs Charlie Flanagan's interview in this newspaperwith The Irish Times yesterday made clear.

Hard border

What is not clear, however, is whether the EU will agree. And that may not be clear for some time. Ms May has said she wants to see no return to a hard border between the two parts of Ireland, and she wants to see a maintenance of the common travel area between the two. At the Conservative party conference in Birmingham on Sunday, she revealed she would trigger the article 50 exit process next March, meaning Britain will formally leave the EU in early 2019.

Ms May has rejected the idea she is choosing a “hard Brexit” – in which Britain leaves without maintaining access to the single market on favourable terms – but the logic of her position is that, while Britain will seek an amicable and mutually beneficial departure from the EU, she is prepared to leave anyway if that’s not on offer in terms she finds congenial.

The markets have taken note, with sterling receiving a battering in recent days. Chancellor of the exchequer Philip Hammond warned of two years of turmoil and uncertainty.

A bad-tempered Brexit is exactly the outcome the Irish Government fears most. It will now have to make preparations for that contingency.

All hinges on the outcome of the EU-UK negotiations. It's impossible to peer into the future of the exit negotiations, which will be long and incredibly complex. One British official told The Irish Times during the summer that negotiating Brexit would be the most complicated process ever attempted by a British government in peace time.

The EU treaties lay out a two-year timeframe for the negotiations, after which the UK is out. Unless a comprehensive agreement is in place by then or, more likely, an interim agreement while negotiations continue – a disorderly and fractious exit is possible.

Economic consequences

The political and economic consequences of that are not pretty, in Ireland especially, but everywhere else too.

Surely neither the EU nor Britain wants such a scenario? Surely governments would not wilfully inflict economic damage on their countries for short-term political ends?

But the entire meaning of the Brexit vote result is that many people in the UK think politics is more important than economics. They chose greater political control – in the shape of the power to limit immigration – over economic benefits of EU membership.

For the EU, economics has only ever been a means to a political end. The union is founded on the idea that binding the economies of former enemies meant they could never again go to war against each other.

Deep in the DNA of each side’s priorities is supremacy of politics over economics. That means that they are likely to bear some economic pain for a political goal. That should make the Irish nervous.