The EU doesn't seem to have increased prosperity, unless I'm missing something? I just think of austerity, the debt crisis in Greece (and the rise of the far right), the euro...
Boris Johnson has warned in the Telegraph here about the Five Presidents Report of June 2015.
He says that "Euro chiefs" ... "want to prop up the euro by creating an all-out economic government of Europe."
"They want a euro-area treasury, with further pooling of tax and budgetary policy. They want to harmonise insolvency law, company law, property rights, social security systems – and there is no way the UK can be unaffected by this process. As the Five Presidents put it: “Much can be already achieved through a deepening of the Single Market, which is important for all 28 EU member states.” So even though Britain is out of the euro, there is nothing we can do to stop our friends from using “single market” legislation to push forward centralising measures that will help prop up the euro (or so they imagine), by aligning EU economic, social and fiscal policies."
Later he says
"So-called “Single Market” measures affect us as much as they affect the eurozone – and the question therefore is what we mean by “Single Market”. The answer is a mystery – because the single market has changed beyond recognition."
The Five Presidents Report even described the euro as "a successful and stable currency".
Lord Mervyn King, former governor of the Bank of England, has said
"Put bluntly, monetary union has created a conflict between a centralised elite on the one hand, and the forces of democracy at the national level on the other."
and as quoted in the Telegraph Euro depression is 'deliberate' EU choice, says former Bank of England chief
"In the euro area, the countries in the periphery have nothing at all to offset austerity. They are simply being asked to cut total spending without any form of demand to compensate. I think that is a serious problem.
"I never imagined that we would ever again in an industrialised country have a depression deeper than the United States experienced in the 1930s and that's what's happened in Greece.
"It is appalling and it has happened almost as a deliberate act of policy which makes it even worse".