A 14-year-old girl who is "too big" for her school uniform has been forced to sit in isolation or stay at home.
Kada Jones arrived back at school this month wearing a grey size 24-26 skirt from Aldi, which she says she wore last year without complaint.
But Portchester Community School in Fareham, Hampshire, says this year the skirt isn't regulation - and removed her from classes.
Kada claims she is unable to wear the skirt it suggests because of her size.
"I've been crying for the past five days - I don't understand, I've done nothing wrong," the girl, from Fareham, said.
"People get put in isolation because they have done something wrong; they've been treating me like I'm not even a human being.
"All I want to do is go to school."
Kada's furious mum Carleen Jones, 54, said: "Kada was in the headmaster's maths class last year, and he never raised an issue with her skirt.
"If she was dressed like a punk rocker or something I would understand, but this skirt is similar to the school ones and is absolutely fine."
She added Kada, who is studying geography, health and social care, history and art alongside the core GCSE subjects, is medically healthy.
However, the school's headteacher insists the Aldi skirt does not match school regulations "in terms of length". He stresses all the 633 pupils at the school must follow the same rules.
Richard Carlyle, headteacher of the school rated Good by Ofsted, said: "It's about the skirt being the appropriate length and appropriate material.
"Miss Jones' skirt wasn't quite up to school regulations in terms of length, but the school is working to find a uniform that is compliant.
"Pupils have a duty to wear the uniform respectfully and with dignity."
It comes after an 11-year-old lad from Cambridgeshire was placed in a behaviour support unit , when his school spotted his black Vans shoes as they breached the school's uniform guidelines.
And in West Yorkshire, a 12-year-old girl was put in isolation this week because her skirt was too deemed short.