Let’s be quite clear. All this is not difficult. This is a matter of principle and if you can’t see this I seriously doubt your intelligence and your integrity. I’m looking at you ET.
The UK signed up to an international agreement. The British government and civil service are staffed by highly intelligent personnel (though the Tory leaders are pure bullshitters). They knew exactly what they signed up for, and the actions they were obliged to take under the agreement. They have deliberately chosen, as a matter of tactics, not to do so.
The fall-out that results from this position is solely the fault of the Tories. The EU may not be “perfect” but they are positive angels in comparison to the arseholes that are running this country.