Britain was in a bad way when it joined the Common Market in 1972, low productivity, lack of investment in infrastructure, labour disputes and rising inflation.
The problem is after all these years, Britain hasn't changed that much. We still have low productivity, lack of investment in infrastructure and rising inflation.
Being in the EU has bought a lot of foreign investment and helped to plug the gaps left by failing industries. With limited access to EU markets, it seems foreign investment will dry up