You’ll get replies along the line of “we grow lots here and we survived the war!”
Our population cannot survive on the food we produce alone, it’s that simple. There are many, many more of us than during the war and so very many more of us live in flags and HOM without gardens for growing food (and not to mention growing food over winter takes time and skill).
Many of the food products that are manufactured in this country are made with ingredients sourced in the EU. The same goes for the likes of loo roll, cleaning products and personal hygiene stuff.
I believe the U.K. produces a little over half of what it consumes, I read the figure as 54% last week. And we have been a country reliant on imports for many hundreds of years.
Getting stuff into the country could become difficult. We don’t know what the process is going to be like and if HMRC will just wave through vehicles if there are major issues (if so then WTF is the point of Brexit?). If vehicles don’t get waved through and why would they, then food will be left to rot on trucks and drivers will reach their hours sitting in queues meaning they can’t drop off and turn around to pick up and drop off more food. It’s a spiral.
I have a friend who works at a major port who has said that areas of one port which were previously carparks where they could inspect vehicles have now been built on. There is nowhere to put a huge number of vehicles that require checks and inspections which is why Operation Stack is a thing.
Also all the lorries that go abroad will need special permits for each of the two parts of the lorries. Where and when does this come into force and when are companies going to deal with it?
If you can afford to - put some extra food into your shopping trolley when you do a big shop. This isn’t panic buying, this is buying in good time and giving supermarkets time to restock within the just in time infrastructure.
If you shop sensibly in good time, it gives time for the food to be replenished and takes you out of the equation when it comes to panic buying further down the line.