The incident is now in the hands of the police as there were multiple witnesses who saw what happened.
A spokesperson for the police said: “Shortly after 4:15pm on Friday 22 September we received a report that a 49 year-old woman had been assaulted on St Marys Road in Portsmouth at around 1:40pm that day.
“A subsequent report was received shortly before 10:00am on Sunday 24 September that a 15 year-old girl had also been assaulted on St Marys Road on Friday 22 September shortly before 1pm.
“Neither was seriously injured.
“Enquiries are ongoing to establish what happened and whether the reports are linked.
In a letter sent to parents, the principal, Natalie Sheppard, said: “Many of you will be aware that on Friday one of our teachers was seriously assaulted by a student. This unprovoked and horrible incident of violence has come as a deep shock to our community and is now a police matter.
"There were numerous witnesses to this incident, which was also captured on CCTV. The seriousness of what happened means that we have already taken strong action – the decision has been made to permanently exclude the student responsible for the attack.
"I want to be absolutely clear that I will always give my team 100% support should they receive abuse of any kind; and that I will similarly always support well-behaved students who treat others with respect and come to learn.”
The principal has also established the expectations from pupils and she has also placed emphasis on the punishment for treating teachers and other pupils disrespectfully.
The letter added: “Whilst the vast majority of our students behave impeccably and follow the rules set by the academy, it is with regret that recently we have seen a small number who are consistently removing themselves from lessons, who are causing disruption to other students’ learning, and who are not following the instructions of staff.
"Therefore, should your child be out of any lesson and fail to follow reasonable instructions from senior staff, they will receive a suspension that will be a
permanent mark on their record. Other sanctions may also be considered.”
A spokesperson from the Academy said: “Incidents like this are incredibly rare and we are taking it extremely seriously. The vast majority of our students behave impeccably – and we will not accept behaviour such as this.
“We took immediate action and permanently excluded the student involved, and have reiterated the high standards we expect of all students. We are also prioritising the well-being of all our staff and students, and look forward to welcoming back the member of staff involved in the coming days.
“We are unable to comment further at this time because of the ongoing police investigation, and are fully supporting the police with their enquiries.”