It would hurt, quite a lot. But then they could just adjust and forget about the UK and do very well selling and buying from each other, with Schengen, no borders, no paperwork, and with no tariffs- and a great variety of conditions and climates within to provide all they need. And labour too. What do you think?
And could of course control everything and everyone that comes in or out of UK.
Brussels police ordered to attend a right wing conference attended by Braverman and Farage