Minister for Social Protection Leo Varadkar’s suggestion that the North remain in the EU single market and customs union after Brexit, removing the need for a Border on the island, is – unlike much of the talk about the issue – at least logical.

It would be the only way to ensure that free movement of people and goods continued between North and South. Unfortunately, however, as with just about everything about Brexit, this is far from straightforward.

Varadkar, who is battling Simon Coveney to lead Fine Gael and become taoiseach whenever Enda Kenny names the day, has put forward the idea, which has similarities with the Sinn Féin concept of the North having a special status.

It will, no doubt, be the subject of some official study here, following the invitation from the chief EU negotiator, Michel Barnier, for ideas on how to tackle the Border conundrum.

If the North did stay in the single market and customs union, it would first require a concession from the EU, which insists that membership requires participants to play by the rules. However, it would also raise some other issues.

It would require, as Varadkar pointed out, customs controls at Irish ports and airports, as goods entered and left the single market. Of course, such controls would be necessary in the Republic’s ports and airports post-Brexit in any case. However the biggest potential stumbling block to Vardakar’s plan, apart from the likely unionist opposition, would be the reaction from businesses in the North.

After Brexit, businesses in the North would still hope to have no customs borders for goods coming to and from the rest of the UK. However, if the North stays in the EU single market and customs union – and the rest of the UK leaves – then this would not be possible. On the flipside, the North’s businesses would have free access s to the single market not only in the Republic but also in the rest of the EU.

However, the rest of the UK is by far the biggest market for the North’s businesses, more than outstripping all exports – and not far off four times sales to the Republic. Varadkar points out that the North did not vote for Brexit. This is true. But the rest of Britain did, and this has changed the economic calculus for the North’s businesses.