Police were called to an incident at the John Colet School after a 13-year-old boy threatened an older pupil with a knife.
Christine McLintock, headteacher at the mixed secondary school, told the Bucks Herald: “A Year 8 student threatened a Year 11 student with a knife – thankfully no one was hurt.
“Staff were quickly alerted to the situation and swiftly dealt with it in line with the school’s procedures.
“The Year 8 student was immediately isolated, the knife confiscated and the police were called.”
Mrs McLintock added: “I would like to reassure all parents that this was an isolated incident and the safety of students and staff is of utmost importance to everyone at the school.
“Threatening and aggressive behaviour is not tolerated at John Colet School and will be dealt with accordingly.”
Police have arrested the teen.
He was bailed pending further inquiries until February 19 while police work with the school to organise safety talks for pupils.
A parent who has two children at the school described the incident as ‘scary’.
He said: “I cannot believe a child so young would be carrying a weapon into school, let alone threatening to use it.
“I hope the headteacher makes sure that this never happens again.”
Mrs McLintock wrote to parents in an email to explain what had happened and to reassure them their children are safe.
The incident took place on Friday morning and police confirmed the boy was arrested soon after.