Police have arrested a 16-year-old boy after a teenage girl was stabbed at a secondary school. The victim was taken to hospital with minor injuries after the incident at Thorpe St Andrew School, near Norwich, on Wednesday. Pupils were told to switch off their phones and hide under their desks when the school was put into lockdown at about 10:25 GMT, the BBC has been told. Norfolk Police said the boy was arrested on suspicion of causing grievous bodily harm with intent after searches of the area. He was taken to Wymondham Police Investigation Centre for questioning. Laundry Lane remained shut in the aftermath of the incident, while images circulated on social media showed armed officers searching the school. About 150 parents gathered at the school gates as they awaited news on their children, some of whom had messaged to say they were scared and hiding in classrooms.…