It was a lie by David Cameron to appease the idiot group of conservative voters that thought Europe was the cause of all ills. A lie that blew up on his face, because he didn't (nor Johnson & co.) expect it to win. And a lie that blew in the British voters' face when it turned out that exiting Europe was a very stupid idea that would not have solved the problem of being a country still in toxic and unresolved love with its imperialistic, classist past.
The day Britain stops believing their are at the top of the most powerful empire in the world, but simply a rich island off the coast of a very powerful trading bloc, they might make something of their position.
The economic way out for Britain requires a lot of humility and taking a serious look at the sort of people that are running this country. Thinking that EU scum are coming here to steal your jobs is certainly not the way to go about it.
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Bonus: Here's Boris Johnson, champion of Vote Leave, after the referendum: https://youtu.be/nbdOsMeVrLw?si=UyVv2_j1M6QcavtC — quite the somber demeanor for someone who has just won a massive gamble.