"Hate-orientated" abuse by pupils using a controversial phone app has prompted a headteacher to send out a warning to parents, pupils and staff.
Steve Riches, of Highams Park School in Handsworth Avenue, has written a letter on the widespread use of Yik Yak and has urged students to delete it from their phones.
The free smart phone app connects nearby users automatically without the need for registration and allows comments to be posted anonymously.
He acted after staff reported seeing posts between pupils which were described as "offensive, harassing, hate-orientated, harmful, defamtory, probably illegal, and are targeted at named individuals."
The use of mobile phones is banned at the school, but pupils are still said to be targeting fellow students.
He added: "This can lead to severe cases of bullying and creates tensions throughout the school community."
Although the terms and conditions of the app state users must be older than 17 to download it, Yik Yak is being used by people under that age.
Scott Freeman, founder of The Cybersmile Foundation, a non-profit organisation tackling all forms of cyber-bullying said: "We are very aware of the problems surrounding Yik Yak, especially in school environments.
"The way that this app is being used to cyberbully and target others highlights the need for emotional education in our schools.
"Although anonymous formats are certainly a breeding ground, cyber-bullying is present across all social media platforms; we would like to see Yik Yak working with organisations like Cybersmile to offer as much support and guidance as they can to their teen user base."
The safer schools officer PC Westall has warned pupils that if a crime is committed using any such app, the person responsible will be tracked down as anything posted on the internet is never truly anonymous.
Lastly, Mr Riches added that he "thought long and hard" about mentioning the app for fear of making more pupils aware, and re-iterated the school’s stance that it takes "any forms of bullying very seriously."