The problem is the linkage. To be a fully effective trading block means no barriers, so borderless. That in turn means transport harmonisation. That in turn means common transport laws and many common laws for the personnel crossing those borders.EU is and should remain a trading block and not an all controlling political experiment, which is exactly what it is.
Then you have a goose and gander situation, what's good for one is good for the other. You can't say common laws for the truck drivers but not for anyone else conducting other business across borders, and once you concede for them, why not tourists as well?
And with common unimpeded borders, no customs etc, it's necessary to have a considerable degree of fiscal harmonisation. And where can the line be drawn between staying and working while visiting or staying and working more permanently, which in turn leads to more harmonisation in reciprocal medical treatments and pension payments?
Once you've gone that far, it's necessary to have a ruling authority like a common court, it cannot be left to member countries courts making conflicting rulings if the above conditions are to be met.
Parliament has already discovered all this during the WA negotiations, which have conceded so much that parliament didn't consider the TM and BJ agreements leaving at all. But there's more concessions certain to be made during the trade agreement negotiations.
By the time it's all over in a few years time, many will be wondering why we even bothered to try leaving since we'll be still so tightly bound.
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