British kids wear school uniform, as has been commented.
I think this is a pity for three reasons;
1/ All the puke about it levelling playing fiels etc. is poop. Kids can sort-out someone's socio-economic status even if they all wear the same clothes. Do people think kids are STUPID are something? I suppose you could require they attend school in white forensic suits and use standard equipment (pens etc.), ban all personal items, and use public transport to get them there... then it would be harder. But the most cited reason for school uniform is poop, it really is.
2/ Kids hate uniform. Loads of pointless time is spent by teachers enforcing uniform rules.
3/ Infantalisation. The English are the worst-dressed slobs in Europe. We practise wearing a uniform as untidily and as negligently as possible for years and get very good at it (or the boys do - the girls try to lolita-eaque their uniforms (shorten the skirts, wear a shirt a size too small, etc.). This means that when we go and work, if we wear 'smart business attire' we look like slobs as we have had no practise. At any meeting of Sales people for a pan-European company the English reps stand out as they look like sacks of shit in their suits. Hell, even our IT geeks look worse than other IT geeks. Deprived of developing style and taste at school, most people never recover. Dutch kids (no uniform) and AMerican kids (no uniform) seem more adult than English kids I have taught, age for age. Treat people like babies who can't dress themselves and you encourage them to behave like 'babies'.