We can't really rule anything out, and that's part of the problem. No one has a clue what's going, including and especially the people making the decisions.
A serious question that has to be asked is how quickly can we 'recover' from a No Deal situation i.e. revert to pre-existing customs procedures?
As quickly as you can hold a second referendum.
(Unless the No Deal is bad enough that a cross-party consensus emerges for rejoining CU/SM - i.e. Norway - but I'm not sure we should wish for that to happen.)
