They need to have the unearned smug arrogance brutally beaten out of them until they understand the unforgivable crimes of their nation, and that they are no longer special or important on the world stage.

So much of the arrogance is just another collar around their necks that someone else can yank to control them. I don't think it ever goes away, so long as the UK is seen as a place worth dominating. People will be told they're special, that they've been robbed of some kind of birthright, and that the only way the can get it back is by going abroad and killing. And that delusion will persist so long as its worth putting money into the island to turn another generation of young people into brigands and crooks.

Once they've cut off the head of their monarch and torn down every monument to their genocidal imperial warlords like Churchill, then the work of uplifting them to sapience can begin.

I'm not holding my breath on that happening. But crazier things have.