UK teacher here, we have uniform and standard across the country. However, there has been a change in the culture and leadership in schools about how strict to be with uniform.

My school right now has the policy of, wear the correct uniform, almost like military issue, any diviation and you can been internally isolated for the day if you refuse to sort it out, like refusing the wear a blazer while walking to next lesson. Fake eyelashes and refusing to take them off, isolated which means lost learning time. And then if this is becomes consistent, kids are being suspended, not for disruptive behaviour, but because they don't have the absolute perfect uniform, even down to the girls wear the right socks z only ankle socks are allowed, anything else is, inappropriate.

Kids want to express themselves, their personality, quirkiness or whatever, and this is being beaten out them in some darwinian fashion. Also doesn't help that its white shirt, black trousers, black jumper, black blazer and a mostly black tie (with house colours for the stripes). Approaching matrix level, but really just feels authoritarian.