It’s well worth looking up Tony Benn’s Views on the EU. There’s a good interview on YouTube where he’s talking about the British Constitution and how it evolved over hundreds of years. He said politicians and rulers are its custodians only and were never in any position to horse trade parts of it and give it away as it was never there’s to give away in the first place. He said it’s a bit like being given custody of someone’s classic car on the understanding you return it same as before or better but giving bits of it away.