The last thing this country needs as Brexit looms is further division

Such a hard border, involving immigration as well as tariff controls, would negate many of the most important elements of the Good Friday Agreement and could well undermine the whole Northern Ireland peace process. It is imperative, accordingly, that the Irish Government and every self-respecting political party on this island must do everything possible to prevent such an eventuality taking place.

The first thing NOT to do is to call for a border poll.

This would almost certainly be lost and would in any event create enormous sectarian tensions and divisiveness in Northern Ireland. It would make cooperation between North and South less, rather than more, likely.

What is needed instead is a plan that would attract the (not insubstantial) progressive elements within Ulster unionism without threatening their British identity, to which at least half the Northern Ireland population is still deeply attached.

To square this circle, some mechanism must be found that would allow Northern Ireland to continue to be a part of the United Kingdom while at the same time remaining within the EU.

As everyone is aware, this will be a very difficult task to undertake - but it is not altogether impossible.

For Northern Ireland to remain within the EU after the UK has left, a tariff and immigration boundary would have to be created around the island of Ireland, isolating it from the non-EU territory that Great Britain would become.

This would clearly be at variance with standard EU practice and regulations. However, some exceptions of a comparable nature do already exist. The strategically located Swedish-speaking Aaland Islands in the Baltic Sea fall under full Finnish sovereignty but have been granted a separate tariff and tax status - with full EU blessing. Likewise, Greenland was permitted to exit the EU (in 1985) although it remains an integral part of the Kingdom of Denmark.

There are also the well-known entities of the Isle of Man and the Channel Islands, which have never been part of the EU but are sovereign British dependencies.

All of the above examples are clearly much smaller in terms of both their population and current political importance than Northern Ireland.

On the other hand, Brussels and most of our partners within the EU are only too well aware of the need to preserve the Northern Ireland peace process and to avoid a return to the 30 years of death and devastation that preceded it. Finding support for a compromise proposal in Brussels should not therefore be beyond the capabilities of our diplomatic service.

Furthermore, the Good Friday Agreement is an international treaty which guarantees that close links between North and South on the island will be maintained. These guarantees cannot be unilaterally withdrawn by the British Government. In this respect, it can be argued that Northern Ireland's claim for special treatment by the EU and by Westminster is much stronger than that of Scotland.

The real difficulty without doubt, however, will be the task of persuading at least some Northern unionists that such an arrangement with the EU will not pose a direct threat to their British identity nor to their fiscal links with Britain and with the pound sterling.

At the very least, a pro-EU majority must be forged within the Stormont Assembly if Whitehall is to be forced to pay attention.

If there is no alternative, the DUP and their ilk will have to be left out on a limb of their own making.

This will certainly not be an easy assignment to fulfil but it is one which every Irish nationalist political party on the island should now regard as a priority. Sinn Féin, in particular, must discard its traditional ambivalence towards the EU and also stop talking about border polls and reunification.

It must for once take into account the interests of all the people of this island and persuade enough Northern Protestants that remaining within the EU will not undermine their long-held traditions and beliefs.

Likewise, the Irish Government must stop worrying so much about the Common Travel Area (whose importance in any event is frequently overrated).

It should ensure instead that the focus of its strategy at the forthcoming Brexit negotiations will be first and foremost to prevent any further divisions or hard borders being created on the island of Ireland.

What is at stake is no less than the well-being of all the people of Ireland in the 21st Century.

Dr Niall Holohan is a retired Irish ambassador. He has served for several years with both the Anglo-Irish Secretariat in Belfast and the North/South Ministerial Council in Armagh

Irish Independent