A teenage girl was put in isolation after dying her hair pink to "cheer herself up".
Savannah Sharp, 15, was segregated from her classmates for two days for breaking the uniform policy at St Peter's Academy, in Fenton, Stoke-on-Trent.
But Savannah and her mum claim the decision was unfair as teachers are aware she has anxiety and depression, and had previously turned to self-harming as a way to cope.
"She dyed her hair before half term to cheer herself up. It was a wash in, wash out but when she went into school she was put into isolation for two days," mum Rachel Sharp told Stoke-on-Trent Live today.
"Savannah is in year 11, her GCSE year, and needs to be in lessons because of her exams but they took her out for two days. They basically stopped her from learning.
"I've spoken to the school over the phone and they told me that I need to dye her hair back, but I have refused to do this as it is an infringement on my daughter's human rights to express herself in a way she is comfortable.
"The colour of her hair has no impact on her education. People with dyed hair and tattoos still do their jobs well, but they say it's going against school policy."
Rachel, 48, is concerned her daughter will now turn again to self-harm.
The mum, of Fenton, added: "Savannah is very angry about it, she doesn't know why the colour of her hair matters when her GCSEs are really important. She missed out on her maths and English lessons.
"She's annoyed that she was put into isolation and it's brought her mind back down to a low level. That's why I'm so annoyed at the school picking up on such an insignificant thing.
"Her hair is a nice pale pink, it will eventually wash out and it made her feel better about herself, whereas before she would self-harm.
"I don't see how the colour of her hair can impact on her ability to learn, they're making a mountain out of a mole hill. The most important thing is that Savannah is in school learning for her GCSE exams.
"As long as she is sent into school with a clean uniform, she's willing to learn and is respectful to her teachers that's all that matters."
St Peter's Academy, which Ofsted rated as "Requires Improvewment" after an inspection in May, caters for more than 900 pupils.
Rachel continued: "The school is aware of Savannah's mental health and I'm disappointed in them because they should be helping to make sure her mood is lifted not putting her in isolation where she's alone. Having no one to talk to will affect her mental health.
"I am totally disgusted with the staff at the school."
The school has been approached for comment.
