HERE we are halfway, perhaps, through the latest UK charm offensive in the EU. But this time round we are about to embark on formal negotiation of the actual Brexit deal – the year of wrangling since the invocation of Article 50 has all been mere foreplay. It is time for the UK to show its hand, as our European neighbours politely insist.

Yet the UK seems unwilling, maybe unable, to oblige: not surprising, since it cannot itself decide what it wants out of Brexit. Instead we see diversionary tactics, to get round the stroppy top negotiators in Brussels, Michel Barnier and Jean-Claude Juncker, by trips to European capitals and direct appeals to national leaders to help us out somehow. “Make me an offer,” as Theresa May habitually says. This was reported by the German Chancellor, Angela Merkel, who like the rest of them is more interested in what our Prime Minister has to say for herself.

These 27 leaders resolved right at the outset to preserve a united front among themselves, and they have not changed their minds. For them non-membership of the EU has to be worse than membership, in which there would otherwise be no point. This explains why Barnier, when he mentions Gibraltar, takes the part of Spain. This explains why, when he talks of Northern Ireland, he takes the part of the Irish Republic. “Community preference” has from the start been a basic principle of the EU. For its sake in 1973, we ourselves abandoned our own previously closer trading relations with the countries of the Commonwealth, much to their chagrin. Yet we seem shocked as the operation of the principle now goes into reverse.

We have just seen two stages of the charm offensive. One was Boris Johnson’s speech with its appeal to Remainers for unity inside the UK. Amazingly, the Foreign Secretary had nothing to say about the most divisive challenge in his own brief, future relations with Ireland.

The Republic gives the UK its one land border. Like many borders this long remained turbulent, till the UK and Ireland at last drew on their common European connection to help in pacifying it. After the Good Friday Agreement of 1998 the relations, not only along the border but also across the Irish Sea, grew warmer than at any time in the last 700 years. Now Brexit has made them worse again, and threatens to make them much worse, possibly to the point where the Irish problem wrecks the whole process.

Supported by both government and opposition in Dublin, the Taoiseach, Leo Varadkar, has a simple aim. He won’t accept any result bringing back checkpoints and controls along those 350 miles of border. Yet their return would, once the UK left the EU’s single market and customs union, become “unavoidable”, to use Barnier’s term. If this were to provoke Irish nationalists, it could before long also bring back military blockhouses and armed guards, obvious targets for attack by bomb and bullet. On grounds of security we should at all costs seek to stop such an ill turn of events.

The arguments from principle are even more decisive than the arguments from practice. The UK and the Republic are co-guarantors of the Good Friday Agreement, which functions as both treaty and constitutional authority for Northern Ireland. If it can no longer work then we might possibly revert to the situation that obtained before 1998, with direct rule of the province from London. Certainly there are Democratic Unionists who want this, and so remain obstructive over everything else.

Yet Varadkar has played his hand better. Theresa May has had to give in to him and promise full regulatory alignment between Northern Ireland and the Republic during the period of transition, unless some other, mutually acceptable arrangement could be found to remove the alternative prospect of an immediate hard border.

Now the UK is being asked to do its bit by agreeing to a watertight legal text setting out what full alignment means and how it should work. Dublin is in no doubt what it means: Northern Ireland must follow all EU regulations needed to uphold the Good Friday agreement and to maintain an open economy over the whole island.

That amounts to staying in the EU customs union and single market, whatever legal contortions may disguise the fact. May’s problem is that she has also made a parallel commitment to the Democratic Unionists that Northern Ireland should remain in full alignment with the rest of the UK. And quite apart from the whole Irish aspect, it is a non-negotiable aim of her own hardline Tories that Brexit has at a minimum to mean the end of EU rules we don’t like.

She is therefore in an impossible position. Her reaction is to say as little as possible about anything. Lesson for others: under pressure the UK Government can, even in silence, be moved far in ways it didn’t want to go.

No wonder, as we saw in a second stage of the charm offensive, May urged the EU to “ignore the rule book”. She said this at last week’s conference in Munich on security, including the effect on it of Brexit.

The proceedings there went off peacefully enough, but from several hundred miles away Nicola Sturgeon took the chance to accuse the Prime Minister of betraying the national interest by leaving a gaping hole in security arrangements for the post-Brexit world. True to form, May had ducked the big picture for a smaller one.

What she proposed was a new security treaty between the UK and EU. It might be thought this was hardly necessary because, ever since 1949, NATO has been there for most member states, bringing in the Americans as well to guarantee we have all the arms, men and money we need. Today counter-intelligence grows ever more important and the head of MI6 went along with the Prime Minister to Munich especially so he could join his French and German counterparts in committing themselves to sharing information among European spooks.

If they are that friendly anyway, why the charade about a new treaty? Presumably to offer persuasive evidence that, despite Brexit, the UK wants to remain a reliable partner for its neighbours: in May’s words, “the UK is just as committed to Europe’s security in the future as we have been in the past”. It’s the thought that counts.

For the last couple of years the UK Government has taken little real notice of what Europeans are saying – hence the repeated failure of minds to meet over Brexit. No doubt it needs to be treated as a plus that May can also praise the EU and offer it practical proposals. “Political doctrine and ideology”, she said, “should not be allowed to stand in the way of common action” – presumably that very doctrine and ideology undergirding the successive treaties which have constructed the EU of the present day.

Yet the member states may be unable to make much more of a Prime Minister who blows hot and cold in this way. She could win credibility if she publicly took the intermediate position that a soft Brexit would be more practical, more possible and more beneficial (even if requiring a “rule book”). This, disastrously for her, is the one thing she is most terrified of doing.