Shocking footage showing pupils cutting up white powder and snorting it while in school has emerged on Snapchat - but the headteacher insists the substance was mint imperials.

The 12-second clip was uploaded by the youngsters themselves and shows a teenage boy in his school uniform lining up the powder on a desk, before sniffing it up his nose.

He then appears to celebrate by waving to the camera, smiling, and pretending to have bulging eyes.

The clip is believed to have been widely shared by fellow pupils at the Marsh Academy in New Romney, and has also been seen by parents.

One parent who saw the footage said she was “shocked” that the pupils could have been taking drugs in a classroom, and decided to film the mobile phone footage before it expired from the application.

But school head teacher Shaun Simmons says the school is aware of the footage and has sought to reassure parents.

In a statement he said: “We became aware that a student posted a video on Snapchat shortly after it happened during a break.

“Upon investigation it became clear that the students were using crushed up mint imperials as an inappropriate joke and recorded it.

“While it is clear that there were no drugs used during this incident, it is also clearly behaviour that falls well below the standards we expect of our students. Those involved are being dealt with in line with our behaviour policy.”