He has written to parents asking for their support to prevent their children from taking part in the "misuse of social media".
“We are aware of TikTok videos being created using images of some staff, and Instagram accounts being set up using our names,” he wrote in the letter, dated Friday, May 6.
"Many of the images are sexualised, and the language and tone are wholly inappropriate and offensive.
“We are doing our best to identify the students involved in creating these accounts and images. This activity is illegal and could result in prosecutions as malicious communication.
“Aside from potential illegality, these actions are neither kind nor compassionate and are not in keeping with the ethos we promote.”
Mr Walkden added that the main social media sites should not be accessed by under-13s as they can be used to bully other students and to download illegal or inappropriate content.
He asked parents to ensure pupils under 13 do not have access to social media accounts where the age limit is 13 or above, and said they should speak to their child, whatever that child’s age, about the risks if they continue to follow or create accounts like those he warned about in the letter.
He also recommended that parents sit with their child and look at their phone with them to see the accounts they follow, the content they download and the nature of the messages they are sending, though he said he understood some parents may feel uncomfortable doing so as they wish to allow their children privacy.
Mr Walkden said his primary concern was students’ welfare but he was also worried about the ‘wellbeing and reputation’ of his staff.
“My colleagues are working extremely hard and don’t deserve this so I would ask you to make sure that your child isn’t one of those causing the problem, either directly (by posting such content) or indirectly (by following these accounts or not reporting this activity),” he added.