"chances are that economic growth might plummet."
Generally consensus is for a 2 to 3 percent declined, with some extreme figures on the downside.
Long term numbers are hard to tell. But economics really isn't what's driviv this. It is thee displeasure with the political systems as well as existential concerns, both for the people and for their culture and identify. IE this is an issue that no amount of money can solve.
Economics is and certainly should be part of the debate, but I agree that it is not the whole picture.
I suspect that it is a much bigger factor in the decision making process of better off and better educated people who, on the whole, favour remaining in the EU.
Amongst the red-top reading classes I think the issue of immigration is likely to be higher especially with the "taking our jobs, houses, NHS and school places" propaganda that UKIP likes to push.
These are real issues, of course, but have varying degrees of b**g*r all to do with us being in the EU.
Jobs - lack of UK investment in appropriate training and development - nothing to do with membership of the EU except that they are supplying workers that we need.
NHS - government policy ultimately to privatise the service - nothing to do with membership of EU and promises by "leave" campaigners unlikely to be realised.
Schools - OK, yes, extra pressure from immigrant groups, especially in London but lack of investment in infrastructure given that the population is growing anyway is nothing to do with membership of the EU.
Houses - possibly increased pressure from migrant groups but possibly not. Anyway 30 years of underinvestment by the government has nothing to do with EU membership.