A number of students were searched after a school discovered some of its pupils were adapting stationery equipment into "improvised weapons".

Head teacher at St Joan of Arc Catholic School in Rickmansworth, Peter Sweeney, wrote to parents and carers to tell them about measures they had taken after following up on a "serious concern regarding student safety".

The letter, dated February 12, said a number of students had their bags, jackets, and blazers searched that day.

It added some students were carrying "improvised items" which could be used to "harm others".

Mr Sweeney decided to ban pupils from bringing scissors into school.

The letter sent to parents and carer, seen by the Observer, reads: "As a school we have had to take measures today to follow up a serious concern regarding student safety.

"It has been brought to our attention that some of our students were carrying improvised items on their person or in their bags which could be used to cause harm to others.

"As a consequence of this, we had to take the decision this morning to search a number of students' bags, blazers, and jackets.

"In light of escalating national concerns about knife crime, it is more important than ever that we take every step to ensure the ongoing safety of the students in our care.

"Whilst it is, of course, appropriate for students to have stationery items in their pencil cases, it is totally unacceptable for any student to adapt these stationery items in any way to create any form of weapon or improvised weapon."

In his letter, Mr Sweeney continues: "We would ask you all, as our supportive parent body, to check your son or daughter's pockets, bags, and pencil cases this evening. Please be alert to items such as adapted highlighters, removed or broken sharpening blades or broken compasses.

"We have also made the decision that students will no longer be permitted to bring scissors into school. If students do bring scissors into school, they will be confiscated and will only be returned if parents collect them.

"At St Joan of Arc, we have always taken pride in the supportive and safe environment we create for all our students. Please rest assured that we will always respond to any incident of concern to ensure all our students are safe within school."

St Joan of Arc Catholic School is a Roman Catholic secondary school and sixth form with academy status in Rickmansworth High Street. The school has not provided any further comment.