Ireland before playing Italy in America last year. When Ireland played Italy in Belfast in 2007, the game was designated an away match officially, to get round the formality that under IRFU rules, God Save the Queen would have to be played. Pic INPHO/Dan Sheridan

Thanks to the current political mood on the island, though, I won’t be following this year’s Six Nations with much enthusiasm. Truth be told, I’ve never felt less like I share a common identity with people from southern Ireland.

It’s not just that Brexit has hardened both unionist and nationalist attitudes to the constitutional question, though undoubtedly that is the case.

The EU debate has also exposed an unpleasant anti-British streak in Irish society and revealed deep contempt for Northern Ireland’s right to be treated as a full part of the UK.

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The Republic’s current prime minister, Leo Varadkar, claims that “there will be no return to a border”, as if he doesn’t realise that most of Ulster has been part of a separate jurisdiction since 1921.

His language reflects the delusion, common among his countrymen, that there is no frontier in Ireland, or may as well not be, because British sovereignty here is somehow qualified by the Belfast Agreement.

When unionist northerners explain that they feel Irish, but that they are also British and owe political allegiance to the UK, the reaction, even among well-informed southerners, is usually utter bafflement.

In a recent BT Sport documentary, Shoulder to Shoulder, it was clear that former Ireland captain, Brian O’Driscoll, struggled to understand how Orangemen, for instance, could celebrate their Britishness one weekend and then travel to the Aviva Stadium to roar on Irish rugby players the next.

To O’Driscoll’s credit, he wrestled gamely with this concept, going so far as to play a Lambeg drum on the fringes of a Twelfth of July parade. But the underlying attitude, that all-Ireland sports teams represent an Irish nation that is indistinguishable from the political Irish nation-state, is clearly evident from the symbols and anthems used by most of the teams, as well as the mindset of fans.

When Rory McIlroy tentatively suggested that he might prefer to play golf for Team GB, which represents the UK in the Olympic Games, there was horror and incomprehension in the south.

How could the golfer ‘defect’, when he had already played for Ireland?

The fact that McIlroy had played for a team selected by the Golfing Union of Ireland, which represents both parts of the island, and Olympic teams are linked to particular nation states, in this case the Republic of Ireland, was not a distinction that many could understand.

Of course, the player was abused and harangued until he reversed his decision and then decided, ultimately, that it wasn’t worth playing golf at the Olympics at all.

Northern competitors in other sports, like boxing and hockey, have experienced equally hostile treatment, in comparable situations.

The rugby authorities are alive to some of these sensitivities and they make some efforts to recognise them, with the anthem ‘Ireland’s Call’ and the neutral IRFU flag for example. However, when Ireland played Italy in Belfast in 2007, the game was designated an ‘away match’ officially, to get round the awkward formality that under IRFU rules, God Save the Queen would otherwise have had to be played.

Of course, it was unthinkable to many Irish fans that the British anthem could be used to represent their country at this fixture.

Yet, the Ireland team is supposed to represent the whole island equally, part of which is in the UK. There was a double standard at play that hasn’t quite been forgotten, even by some players.

Rugby is celebrated, with some justification, as a sport that encourages mutual understanding on this island.

Though, even this virtue can be turned to nationalistic purposes and its success is sometimes used to argue that all-Ireland structures should be pursued in a political as well as a sporting sense.

The difference between bringing people together — while respecting their political differences — and bringing the jurisdictions together constitutionally, is not always clearly drawn.

Some of these attitudes would be easier to forgive and ignore if there weren’t daily attempts, including from the Irish government, to ensure Northern Ireland is separated from the rest of the UK by the so-called Brexit backstop. Since the referendum, there’s been a daily diet of pejoratives about the idiotic British and the racist stupidity that has led to them to leaving the EU, even in the most moderate Republic of Ireland newspapers.

The idea has flourished that Brexit will alienate unionists from Great Britain and bring about an all-Ireland state. However, it’s recognised too infrequently that these dynamics work two ways and the uncompromising response from nationalist Ireland may persuade others that modern Irishness simply cannot accommodate a British political allegiance.

And that perception could quickly kill off any affinity we felt previously with the rest of the island.