Bullying from the staff

[FenixWinda]

Has anyone experienced bullying of their secondary school child by teaching staff and successfully resolved it ?
We have a high school teacher openly criticising and making snide remarks about 11y/o child in front of class, apparently trying to provoke a response and when this fails, keeps the child after class when (without witnesses) child was intimidated by teacher asking if they are stupid .....
This in turn has made child late for next class, drawing attention and creating a spiral thats eroding esteem and credibility in front of other staff - real psychological bullying.

You need to go through the school's complaints policy.
Which normally means speaking to the teacher first.
Then if not resolved
Head of department
Head of year/house/community
Then link SLT or HT
then governors.
After that it depends on what type of school it is.

You will to speak in a calm fashion, laying everything out and with either a plan to resolve the issue or what you want the final resolution to be.
You will also need to be open to hearing the teacher's POV.

Sometimes they are resolved as misunderstandings or clashes of personality, other times pupils move classes, and in other cases teachers have been sanctioned and monitored with training.