There costs to Brexit.
Somewhere, a long way back in this string of comments, somebody asked for concrete examples of increased costs for shipping goods to Europe. Back in the '90's I was driving a truck running around Europe and I experienced both sides of the 'Open Borders' decision.
Before 'Open Borders' it took between 1 and 2 hours to get through Customs outbound at Dover and between 4 and 6 hours in bound wherever, then typically the same on the return trip. After 'Open Borders' I collected and checked the paper work at wherever I loaded. The next time anybody looked at it was when I handed it in at the receiving office of wherever I was delivering. And, again, the same on the return trip.
So, a cost saving of between 5 and 8 hours of truck and driver's costs on each trip with 'Open Borders'.
I suspect that international transport in/out of the UK will revert to the 'Before Open Borders' situation after Brexit, especially in the event of a 'no deal' scenario. And this is a real cost on every load in and out of the UK.