She is a dark brooding girl with a large physical presence. Jessie, as we will call her, is a threat on legs.
The pupils have a bit of a thrill with the disruption that she causes.
However, they don't want to be involved themselves. Jessie does the things you just wouldn't dare. There are young teachers who are frightened of her - even though she is just 13. But if you were a teacher you would understand.
Jessie sneers, she scowls, she rages. In any argument - and there are many - she invades personal space. She is in your face.
Perhaps one day there will be a knife in those large hands as we anticipate her trying to thump someone. Naturally, she has the full complement of social workers. She has learned all the proper words. Jessie can speak quite articulately about her rage and about managing her anger but she is still a ticking time bomb of unhappiness.
For no apparent reason, the troubled bully started targeting a petite, lively and attractive teacher.
Perhaps the teacher represented what Jessie wanted to be. Who knows? But Jessie followed her, invading her space, standing in her shadow. Her threats were enough to unsettle and to intimidate.
How is it possible for a child to terrorise a professional adult? But Jessie is bigger than many of the staff and certainly stronger than me. She is also unpredictable. For a moment, her bullying antics gives her some status and attention. Jessie could not rival this teacher's thought, sophistication or probably match her successful career. She set out to destroy what she didn't have.
Yes, Jessie is troubled. But there comes a point at which the school community can no longer support her presence. It is the end of the road. We feel sorry for her father who is completely out of his depth in dealing with his daughter.
Her mother will try to beat her, her father will shout at me down the phone. But it won't change Jessie. She has had our time and now we have others to think of. She wants to be a different person, she tells me, but she doesn't know what to do.
"I want to be good at Welsh," she says. But she doesn't try hard. So we have removed her from school and sentenced her to a dark and forbidding future.
What will happen to her? I should care but I find it difficult. Jessie hates everyone, herself most of all. But this school has no place for hatred and it was time to act.