That sucks I'm so sorry you had to deal with that at such a young age
My experience was the opposite; primary school was great, I think of that time as my happy innocent carefree years.
Secondary school was a bloody nightmare. We lived in a pretty rough inner city area, most, if not all, of the kids were being raised in poverty. Many of them were in care / foster homes, and had all the issues that comes with. Bullying, drugs, alcohol, SA, violence etc were rife.
If you weren't in a gang, you were the victim of gangs. You had no choice but to stick with a mob of mates for your own safety.
One of my friends stood up to a gang of bully girls and was found in the loos unconscious in a pool of blood.
The police came into the school and arrested them all for GBH, but didnt take any further action and they were back in school within the week. My friend never returned to school because her life was literally in danger and nobody cared.
We also had a deputy head who was a total nonce (an ex-policemen no less!), who could always be found lurking around the girls toilets "to stop people smoking" it was an open secret around the school that he had a "thing" for underage girls.
We all used to laugh about him but if you were in the loo by yourself and heard his footsteps, you'd get scared. He was seriously creepy.
SA was a daily occurrence, it wasnt even frowned upon. Boys could do whatever they liked to us and it was "Ah but boys will be boys" / "Just ignore it" etc. One girl suffered a serious SA by multiple boys in busy corridor between lessons, nothing was done, our PE teacher who broke it up just shouted at them all to get to class, left the poor girl in tears with her shirt ripped. Her parents called the police, the boys were "spoken to", the school denied any knowledge of the incident despite there being a whole corridor of witnesses, and so the girl was "spoken to" for "causing trouble" -she never returned to the school either.
That school was where your innocent child-like hopes and dreams all died. Horrible place.
I get why private education is popular in and around London, people arent being snobby, they just want their kids to be safe!