I think the strongest reason for leaving the EU is that its become a completely unwieldy institution, incapable of sensible decision making. 28 diverse countries pulling in different directions.
But that's also the reason why I think it would be impossible for the UK to negotiate a favourable trade deal post Brexit. If the UK were negotiating with a completely integrated EU then money would prevail. The imperative to avoid negative trade consequences would be paramount. But that's not what will happen. The UK will ostensibly negotiate with the EU, but in reality will have to negotiate a deal that is acceptable to all of the other 27 countries. And those 27 countries all have their internal political considerations.
The northern EU countries such as Germany & France will be heavily leaned on by their big exporting companies. Money will be their primary consideration. But its not the be all and end all. Trade with the UK comprises roughly 8% of their exports, a sizeable amount but not critical. They will face huge internal political pressures from voters who will be aghast at the prospect of the UK escaping its obligations to the EU whilst retaining favourable trading links.
For other EU countries, especially those in eastern Europe, trade just isn't as big deal as free movement of labour, They would happily veto a deal that allowed the UK to impose restrictions on EU immigration or curtailed benefits payments.
Add to the mix the EU bureaucrats who will be desperate to avoid contagion, other EU countries seeing that the UK is prospering outside of the EU and deciding to do the same,
In the end there will be a trade deal. But not a good one.
