By law, all state (not private) schools must have a behaviour policy in place that includes measures to prevent all forms of bullying among pupils.
This policy is decided by the school. All teachers, pupils and parents must be told what it is. School staff will deal with bullying in different ways, depending on how serious the bullying is.
They might deal with it in school, for example by disciplining bullies, or they might report it to the police or social services.
Any discipline must take account of special educational needs or disabilities that the pupils involved may have.
You can complain about a school if you think it hasn’t dealt with your concerns. www.gov.uk/complain-about-school