I usually fell back on considering the reverse of the question, because more is often known about the reverse problem. Instead of considering the pros and cons of leaving the EU, consider what we would decide if asked whether to join the present EU from being a world trading country. Think of the following scenario :-
We are at present trading on a major scale with our Commonwealth partners, the USA, China and the EFTA countries, roughly half the world population, including three of the fastest growing countries (I know that China is having problems, but it is still growing at an enviable four per cent plus).
We are the oldest democracy in the world, free to make our own laws, set our taxes, control our own fishing areas and support our own industries and farming.
We can raise tariffs to prevent dumping of excess steel, oil etc and so protect our own industries.
We are now being asked whether we wish to give all this up to join the EU, a small group of European countries, the majority of whom have very weak economies (some of whom are getting weaker by the day because they have to trade in euros which are much stronger than their own currencies would be).
The EU is run by unelected, overpaid bureaucrats who will take over many of the activities of our Parliament and rule over how much fish we can catch in our local seas, demand huge payments to support German and French farmers, while granting our more efficient farmers a mere pittance, set many laws etc. I think most people would regard anyone voting to join such an organisation as being mad. So, looking at the present problem, why should anyone vote to stay in the EU at the coming referendum.
People talk about our defence and safety, but being a member of NATO is much safer than being a member of the EU (France soon asked to rejoin Nato when it decided to rely on the EU)
Our intelligence system is much better than that of any of the EU countries and we have better connections to other capable organisations (the EU had no idea that the Paris and Brussels outrages were being planned, whereas we have detected several groups in the UK and frustrated them).
We can rebuild our trade with the commonwealth and EFTA once free of the EU and give support to our industries and farmers once we stop supporting the lame ducks of the EU.
I could go on, but suffice it to say that despite the suffering of the 20s, 30s, 40s, and 50s, I prefer the democratic freedom of those days to the frustrations of today.
K W Newby