No, it didn't.
It is in the process of doing so, but it hasn't left yet.
But if Brussel's bureaucracy behaved more reasonably, UK would not run away from European Union.
Anti-EU sentiment is generally driven by national politicians who somehow always seem to cast blame on the EU when things go bad and take credit themselves when things go well. Even going so far as taking credit for implementing laws they were actually forced to implement by the union.