Steve, we currently have to impose tariffs on nonEU food.
Food will be cheaper for us when we do not, and EU food is more expensive than on the world market. They will not be able to sell their food to anyone else. Losing our market will enrage their farmers.

If EU impose tariffs on our exports to them it will hurt a bit, but the low pound makes our exports more attractive to everyone, and we will not have squandered billions to prop up EU.