EU customs union and the Irish border

“In May, when visiting Northern Ireland, [David Lidington] said if the UK was not part of the [EU] customs union then there would have to be custom checks at the border. And he said that for anyone to pretend otherwise would be, and I quote, ‘flying in the face of reality’.”

Emily Thornberry MP, 7 December 2016

“The Prime Minister and the Northern Ireland Secretary have repeatedly made it clear, as indeed has the Irish government, that we want to see the very longstanding common travel arrangements and the free trade arrangements across the Irish border continue”.

David Lidington MP, 7 December 2016

It’s true that politicians on both sides of the Irish Sea have repeatedly said that there shouldn’t be customs checks on the Northern Irish border. The problem, for those worried about the prospect, is that it’s not their choice to make.

The government’s position before the referendum was that “outside the EU’s Customs Union, it would be necessary to impose customs checks on the movement of goods across the border”.

Mr Lidington’s remarks in May reflect the official line at the time, although they seem to have been about the Common Travel Area facilitating the movement of people rather than customs checks on goods. But the point he made can be applied equally to customs checks: “this would depend on what Ireland's obligations were with an EU of 27”.

The UK can’t negotiate directly with Ireland to keep free trade across the border. Trade negotiations are an all-EU matter—individual countries like Ireland aren’t allowed to strike their own deals.

Even if an EU-UK trade agreement is reached, with the UK outside the customs union there would still have to be some kind of customs checks on the Irish border. That’s because such agreements come with ‘rules of origin’ to verify that goods purporting to be from Ireland don’t actually come from, say, China. These rules of origin would need to be enforced somehow.

We go into more detail in this piece.