It's not about the law
The disagreements over UK/EU fishing rights and the Northern Ireland Protocol have concentrated on what the TCA actually says, what the legal powers are for both sides and what they can and cannot do.
If France imposed sanctions on the UK over fishing or the EU over Northern Ireland, then there would be a long and complicated series of meetings, horse trading, negotiations, arbitration and legal appeals. But this is not the whole story.
The borders between the UK and the EU are running quite smoothly at the moment, or as smoothly as they can considering the new barriers and red tape Brexit has thrown up.
But like all such arrangements a great deal demands on good will. No one should doubt the French government’s ability to work to rule, to go slow, to reject forms for spelling mistakes or insist on searching every second lorry in a clamp down on say, drugs or illegal immigration.
The UK could do the same, but even if it did introduce a go slow, it would hurt the UK far more than the EU. This is the real sword hanging over the UK.
The UK can then, of course, blame the French for all its problems. Given the record of this Government it will see that as a win.
But the country will suffer, even if it wins every appeal and court case the country will suffer.
Economics, trade and Brexit, not necessarily in that order but the dog always comes first.