All the strict uniform policy did for my DD was show her up for being from a family that couldn't keep up financially for a time. She wasn't the only one.
She was put in isolation for the wrong shoes, for a week, there was a very good reason for me not being able to meet the replacement requirements of 24 hours to get the 'right' shoes.
But well rules are rules and so they put her in isolation and then failed to intervene when she was bullied on the bus there and back and after the shoes being replaced - for being put in isolation for not having the right shoes.
She had two choices, tell the truth when asked by the other kids or pretend to be rebelling. She chose to tell the truth and was then a target.
So great job there by the school of levelling the field hey and not making kids from a poorer background stand out? Like we're told uniform is supposed to do.
It was the only time there was a uniform 'violation' from her, I made sure she had the uniform clean and in good condition and she had all the equipment needed. And only happened through circumstances beyond our control.
I lost faith in the school and so did she. Took the work of a couple of good teachers as well as me to get her to re-engage again because in her own words, she'd been punished for being poor, and then left to deal with the bullying because of that, as well as not allowed to be involved in lessons for a week so her education affected too. It wasn't like she turned up wearing 6 inch stilettos, open toes sandals or clown shoes, they were normal (not branded) trainers that were suitable for PE. So no safety issues there.
So no, I don't believe that it levels everyone, it would only do that if uniform were provided to everyone regardless of their financial status*. It's no different to kids wearing normal clothes in that regard because people get what they can afford and if things can't be replaced from being stolen/lost/broken or outgrown and then punishment is issued on the basis of that you're just actually drawing attention to it. And the fact that you can blatantly tell the difference between a £20 pair of 'plain black shoes' or a £200 pair, and both meet the criteria, make a mockery out of the idea really.
I can see it with things like skirts rolled up, shirts not tucked in, buttons undone, heavy make up, jewellery etc, that's something the child themselves has control over and they can choose to try and rebel and then face the concequences. I can also see it on the grounds of safety where shoes etc are concerned.
*I'm not suggesting that schools provide uniforms before someone starts demanding where the money would come from, just that unless you provide the actual garments it's unfair to punish people who can't afford to buy them initially or replace them within prescribed timetables that aren't realistic.