From: Ed. - PM
Date: 27 Sep 17 - 10:01 AM
You might care to read this article, Nigel...
Brexiters are being naïve over US trade

Okay, I've read that.
It seems this is triggered because of disputes between USA & Canada (something I suggested above).
It is also clear that the arguments about relative market size are exactly the same ones that those in favour of Brexit have been making about the future EU/UK trade position.