Sorry, but that’s not the case. Trade deals with non-EU countries are negotiated and agreed by the EU as a whole, not by the individual member states. The treaty rules oblige member states to abide by this - if they didn’t, it would make nonsense of, for instance, the EU customs union. In consequence, throughout the years of EU membership the UK has had no trade negotiators of its own (although there have been British trade negotiators working for the EU), and has had to recruit trained and skilled negotiators from elsewhere (particularly Canada and Australia) to gear up for the freedom to negotiate post-Brexit.
I get your point. But the UK could have negotiated their own trade agreements and lived with the repercussions. They just chose to go along with the EU restrictions. The Common Market, which was focused on the Eurozone, was never intended to subsume national sovereignty for its members outside that region. That it was allowed to morph itself into a latter day Roman Empire that claimed powers it never should have had is a testament to the craven nature of the European bureaucracy and the cowardliness of most of its European subjects. Until now, that is...