i probably missed a lot of what the old 'common market' was meant to be being an early teen but i understood it was to balance out trade in europe (basically, you have to import xxx amount from one country to export xxx amount to that country) which sounds good, having a guaranteed export route for your product(s) but as we soon found it caused a lot of food mountains and liquid lakes and a lot of problems as countries started to complain that what they were importing were not as good as what they were exporting so food regulation became prominent (we have all heard of the amount of rules regarding bananas) and the modified food came about.
industries were taken from one country and started up in others, so they had more to export, i beilieve all of this basically became a 'false economy'...we all hear about the fish quotas iirc it all started because the british isles had it's own limit around our shores which was very well stocked and gave our industry some healthy catches, parts of europe complained that they were not allowed within that limit so the agreement was made to allow them in, i seem to recall many a fishermen being interviewed on the news complaining that their own quotas had been limited to a point it was barely worth going out and another once proud industry died off...my village had 3 farmers within it and a few more around the area, grain and potatoe fields were everywhere, a few cattle fields (both milk and beef) plus a few turnip fields was pretty much the main stay, i used to do the potatoe picking job every year, it filled a good month which gave some welcome extra pocket money then one year there was only 4 days work, the farm had been told only to grow a few and move other fields onto this rape seed oil (or oil seed rape, can never remember exactly the name)...now there is 1 farm on the outskirts and others have been taken over and 'diversified' with paintball/offroad/fisheries.
i voted leave in the hope that some of our industries would get that boost they needed, unfortunately we at the time had a bunch of half wits that had no plan of action because they did not expect the 'leave' vote to win, they then p1ssed around with their own leadership and tried to get what seemed to be pretty much our established EU agreement but without our membership, resulting in the EU just laughing at us then they 'fell in lucky' with covid giving them a damned good excuse, it was a complete shambles and i still feel if handled the right way it would have helped us.