In addition to Groundloop's response, I would add that EASA and flight safety are not the same, as witnessed with the new FTLs.
Notapilot, the UK us a full member of EASA. Whether that changes depends on the UK government, but it doesn't have to leave - as others said, EASA and the EU are not the same thing, and the UK followed all aspects of EU membership except the currency, which is why so many people are fed up with it (just like a hell of a lot of other Europeans). UK adherence to EU dictat was enforced far more rigorously and unfairly than anyone else's, so your idea that we didn't follow the rules is very, very mistaken.