I agree MOnica. It's unrealistic to suggest that the UK will ever be self-sufficient in food. It's also ludicrous to suggest that agriculture and fishing aren't important - to the economy, employment, the environment or anything else.
What the government seems to be saying is that farming will no longer be able to rely on subsidies. That makes sense from a purely economic point of view (maybe), but there would be all sorts of repercussions. I don't think it was what farmers thought they were voting for before the referendum.
Apparently, the UK has a trade surplus on fish with the EU. British fishermen actually catch loads of fish, but the British don't like eating it, so we export what we catch and import what we want to eat.
The UK also has a trade surplus on barley, which is used mainly for animal feed, but we have to import wheat, especially the high protein wheat used for bread, from North America and Germany.
The UK also imports rice, tea, coffee and loads of other foodstuffs, which can't be grown in the UK. We also import 95% of our wine.
Personally, I hardly eat anything made from grain, including bread, and rarely eat root vegetables, so I'd be a bit lost if the UK didn't import anything. I don't drink alcohol, so that wouldn't bother me, but I think most people would be put out. Most British-grown strawberries and tomatoes are grown hydroponically under glass/plastic and lack taste. I can't see the country choosing to live on only what could be produced in the UK.
I don't really fancy a diet of potatoes, eels and barley. 