Two 14-year-old pupils and a 27-year-old male staff member were injured in the incident For free real time breaking news alerts sent straight to your inbox sign up to our breaking news emails Sign up to our free breaking news emails Sign up to our free breaking news emails Email * SIGN UP I would like to be emailed about offers, events and updates from The Independent. Read our Privacy notice A 14-year-old girl has been charged with three counts of attempted murder following a knife attack at a