Well, who'd a thunk it. Perhaps it isn't quite so simple and straightforward after all. Here's a headline from the Business section of the Daily Telegraph today:
"Nissan warns Sunderland plant can't survive no-deal Brexit. Carmaker said it would not be able to stand by its commitment to Sunderland if the UK failed to secure tariff-free access to EU markets."
Doesn't life have an irritating habit of appearing to be simple, encouraging people to make simplistic assumptions, only for it to show itself as being (to paraphrase Ben Goldacre) a bit more complicated than it first appeared.