As the Brexit shadow-boxing goes on between London and Brussels, our Government has aligned itself firmly with the EU. For the moment,this is an entirely sensible strategy. No point cosying up to Theresa May’s government when it cannot decide what it wants itself.

But just how far will our European partners go to fight against any return of Border controls on the island of Ireland? The Government welcomed the commitment in the EU document this week that everything possible must be done to avoid the creation of a “ hard Border” on the island. Politically this is important, but practically no one has defined what is meant by a “ hard” Border. By using this ambiguous phrase, Europe has given itself wriggle room.

The European Commission added that solutions to the Border issue “must respect the proper functioning of the internal market and of the customs union as well as the integrity and effectiveness of the union legal order”.

This is more than bureaucratic blah. European flexibility in seeking a solution for an Irish Border only goes so far. Above all, EU rules must be respected. The single market cannot be interfered with.

This is entirely understandable from the European point of view – it cannot let Britain leave and then write its own rules .

The trouble for Ireland is that when you couple this with Britain’s stated goal of leaving the customs union, there is only one outcome – the trade Border is coming back.

No clean solution

The commission pointed back at London and said: “You come up with a solution for this.” But everyone knows there is no clean solution to the Border conundrum, unless Britain does stay in the customs union. Brussels has said that the early proposals from London for a “frictionless” Border won’t work – they breach EU rules.

Pretending that flexibility and imagination can somehow solve all this is no more than a smokescreen. Boris Johnson said it should not be “beyond the wit of man” to find a solution, but nearly 15 months on from the Brexit vote no one has managed to do so.

The worry is that neither London nor Brussels see the status quo on the Irish Border as a bottom line

All other routes, apart from Britain staying in the customs union, are problematic. You could give the North a kind of special status after Brexit, allowing it to remain in the customs union while the rest of the UK left. This would remove the need for a Border on the island, but create a new one between the North and the UK. Presumably Unionists and the North’s businesses – who do much more trade with Britain than with the Republic – would find this unacceptable, as would London.

London has suggested a new customs union between it and the EU, but its desire to do trade deals with third countries after Brexit would still be likely to require some border checks.

Temporary membership of the customs Union for Britain for a period after it leaves has also been suggested - and has some support in London. Dublin would welcome this, though it would only delay facing up to the Border issue.

Tricky political calls

Ireland may face some really tricky political calls on this in the months ahead. Irish issues are one area where the EU says progress must be made before the talks go on to discuss UK/EU trade.

How much progress do we believe is needed before agreeing that enough has been done for the talks to go to the next stage? And if Britain does say it will leave the customs union, do we then accept the return of some kind of Border and engage in discussions on how to minimise the damage? Or is it credible to just keep saying “no”?

For now, what Brussels and Dublin are up to is trying to push the political discussion in London in the direction of a softer Brexit. By putting the responsibility of solving the Border problem back to the UK, Brussels will hope to provide support to the soft Brexit camp.

But the debate in Britain keeps heading down the same cul de sac. Britain wants to control migration and do new trade deals with third countries. This is not compatible with staying in the EU single market and customs union, or with having “frictionless” borders with the EU.

For the moment, the “don’t hit us now with the peace process in our arms” approach from Dublin has got political traction. And so it should.

But the worry is that neither London nor Brussels see the status quo on the Irish Border as a bottom line.

London puts a higher priority on leaving the customs union, controlling migration and doing new trade deals with other countries. Brussels and the other EU countries want, above all, to protect the single market.

Peace process

We could get badly caught in the middle here. We could, in time, be getting quiet phone calls from Brussels and Berlin, asking if we could not live with some kind of a Border and whether some unobtrusive controls would really spell the end of the peace process. If this happens, then do we just hold the hard line? Or do we accept that some kind of Border is inevitable and work to minimise the damage? For this to have any chance of working, Brussels would need to show some of the flexibility and imagination it is championing. And still it would be a Border.

For the moment, the not-an-inch tactic being taken by the Irish Government seems to make sense. But support from Brussels will only go so far and the Irish Border is down London’s list of priorities. We could be left exposed. If the financial crisis taught us anything it is that, in the world of high international diplomacy, you are essentially on your own.