Basically you let service failures and infrastructure shortcomings pile-up as a direct consequence of your economic settlement, with successive governments skating around the problems, occasionally bearing witness, making sounds associated with concern, leave it all simmering...

Eventually the opportunist far Right start circling the service/infrastructure flash-points with their flags and age-old diagnosis - it’s the outsiders to blame - to which history, like it or lump it, shows X% of people inevitably respond favourably, put that on a fast boil...

Until eventually that thickens and rises to a point where successive governments take note and can then choose whether to change the economic settlement and address the service/infrastructure shortcomings or not. Ours preferred the latter route. And so now we’ll leave the EU.

I’ll always remember that our response to the almost banally simple lesson of recent European history - extremism feeds on people governments leave behind - was ‘Oh but that won’t happen to us, because reasons’.