It’s rare enough that a story involves Bertie Ahern, the Irish Border and chlorine-washed chicken, but some key developments this week highlight precisely the economic problem with the Border after Brexit. There are, of course, key political issues here too, but the crux of the dilemma relates to the economy and to trade. And this will be a tricky one to solve.

The key issue is that as things stand Britain has said it will leave the EU single market after Brexit and, crucially, that it will also leave the customs union. The customs union is the agreement which allows goods to move freely across EU borders.

A vital part of the customs union is that there in place what is called a common external tariff. In other words whenever goods from outside the EU enter the union, they are subject to the same controls and the same tariffs, or import duties, no matter where they enter. In this way, once goods have entered into the customs union from a third country at one point, they can then circulate freely across the union.

Now let’s introduce the chlorine washed chicken. There was a bit of a row in the UK this week over proposals for a post-Brexit free trade deal with the US and suggestions that this would allow chlorine washed chicken from the US into the UK. In the US, chicken is regularly washed - or rinsed - with chlorine after slaughtering. This is banned in the EU, not because it is unsafe as such, but because the EU says it wants to ensure high standards right through the slaughtering process.

Now it is unclear how this would be dealt with in any US/UK deal, but that’s not the point. If it isn’t chlorine washed chicken it could be Argentinian beef, butter from New Zealand or an engineering product from the Far East. After Brexit , a border is needed somewhere between Britain and the EU to control the movement of such products, make sure appropriate tariffs are applied on goods entering the customs union and that complex regulations on where products come from and their safety are met.

Frontline economy

Ireland, as the only country with a land Border to the UK, is in the frontline. The two most obvious solutions are to have the Border on the island of Ireland - and have the controls there - or to have it at ports and airports leaving and coming in to Ireland. The latter solution would be better for the Government, but it would be far from ideal, imposing new requirements and barriers on trade with Britain. But this would probably be preferable to the erection of new Border controls on the island, with all the political implications that would bring.

For the North, meanwhile, as well as the political sensitivities, there are economic issues. The Republic is a significant trading partner, but of course companies in the North sell as lot more to Britain. For this reason the idea of new controls at Larne and other ports on goods moving to the UK will not go down well.

This has all been obvious since the Brexit vote. So former taoiseach Bertie Ahern is correct when he says that a year has been wasted in terms of looking for a solution, though the Irish Government probably had little option with first the UK general election and then chaos in Westminster over the UK stance. How do you negotiate with that?

The public stance of the Government is that Britain has created this problem and it is up to it to solve it. The ideal solution would be if Britain stayed in the customs union, greatly reducing the Border problem.

Right now there are soundings that Britain might seek to remain in the union for a transition period of some years after Brexit. But once it leaves the union, the problem immediately appears - how do you control goods entering the EU customs union? Technology might make a Border, wherever it is, less intrusive. But it will not remove it

There are a range of other possible solutions which have been touted, such as the North remaining in the customs union, or having some other type of special status. But none of these solutions are perfect. When it comes to the Border after Brexit we are, unfortunately, talking about damage limitation.