Leaving a customs union isn't the same thing as setting up a border.
Leaving the EU customs union will involve some sort of border checks on goods entering Britain.
“Will we continue membership of the customs union, or are we going to see border checks introduced between Northern Ireland and the Republic?... On Monday, the Prime Minister said the [EU] customs union was not a binary choice. I can't think of anything other than a binary choice is [sic] whether you have a border or whether you don't have a border.”
Jeremy Corbyn, 26 October 2016
“The fact that he seems to confuse a customs union with a border, where they are actually two different issues, shows why it is important that it is this party that is in Government and not his.”Theresa May, 26 October 2016
It seems odd to say that a customs union doesn’t involve borders.
The most famous example of a customs union, as the OECD puts it, is the EU’s version (although some non-EU countries are also part of it, notably Turkey). It’s different to the ‘single market’, which is about the EU’s internal trade rules rather than its relationship with external countries.
“If France had zero tariffs on Japanese whisky, but Britain had a 10% tariff, then it would be a profitable wheeze to export Japanese whisky to France, and thence (freely) to Britain. So Britain would have to carefully monitor whisky imports from France, and slap a tariff on any Japanese stuff sneaking in (so-called “rules of origin” regulations).”
Such rules of origin checks are in place between the EU and Norway, for example, because the latter isn’t in the customs union. That suggests that if the UK were outside the customs union, but Ireland remained within it, the same would have to happen on the Northern Irish land border.
Does all this constitute a “border”? As a general concept: yes. It’s a legal barrier between countries.
In practical, physical terms: not necessarily. As we’ve discussed before, customs checks between Sweden and Norway are fairly light touch. There will have to be checks on products crossing the Irish border, but they might not be particularly intrusive.
Mrs May could be saying that people travelling between countries won’t experience a “border” in these circumstances. It’s true that passport controls are a different issue.
Update (15 August 2017)
This factcheck is part of a roundup of Prime Minister's Questions. Read the roundup.
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