Internalising markets, whether in a sole country or a cartel, has been proven, many times, to be a disaster. Thanks to this policy, the EU is so far behind in terms of economic flexibility, energy production and technology, it can no longer catch up.
The EU model was predicated on a "United States of Europe", in spite of the introduction of the Euro, the bloc has failed to introduce a common taxation framework and establish a bank of last resort. The ECB is basically a dead flogged horse that has no power to exert the fiscal controls necessary to moderate the EU's diverse economic structure.
And that structure is literally falling apart, on the news, every day.
Since Brexit, the UK economy has diversified and expanded into numerous global markets. The banking industry is regretting their move to Paris and Frankfurt and are moving back to London, there's British seafood products on sale in Japan at $100/kg and the "beleaguered" car industry is doing just fine. And so on.
The only thing that will scupper this success is the Labour government and the incoherent net-zero ideology of the fu*kwit Ed Milliband. With UK energy prices approaching 4x it's neighbours, that genius has just denied the UK any chance of leveling the playing field by cancelling the UK's only energy safety net. With a net global emissions reduction of about 0.001%. Stupid c**t.