Three boys have been arrested after a suspected acid attack on three fellow pupils at a school in east London.
The boys, aged 12, 13 and 15, were detained on suspicion of causing grievous bodily harm following an incident involving a "noxious substance" at Sydney Russell School in Dagenham on Wednesday afternoon (22 February).
Two girls and a boy were taken to an east London hospital for treatment, police said. They have all since been discharged.
A staff member at the mixed-gender secondary school – rated "outstanding" by Ofsted in 2013 – told IBTimes UK the incident occurred within one classroom, which was later contained.
Head teacher Janis Davies told the Barking and Dagenham Post: "At lunchtime three boys were involved in stupid behaviour spraying some harmful liquid around. We aren't clear what it was exactly.
"Staff were on the scene straight away, three pupils were taken to hospital but were all back home later that day. No long-term effects are expected.
"The three boys are not allowed into school until a full investigation has taken place. If the facts are as they seem to be they will not be returning to Sydney Russell."
The police did not reveal the exact substance used in the attack.
Witnesses described seeing a large number of police and ambulance crews at the school as emergency workers dealt with the incident.
A Met Police spokesman said: "Police were called by the London Ambulance Service to Sydney Russell School in Parsloes Avenue, Dagenham, at 14.11hrs on Wednesday, 22 February to reports of a disturbance involving youths where a noxious substance had been used.
"Three people, believed to be two females and one male, were taken to an east London hospital for treatment. They have all since been discharged.
"Three males, aged 12, 13 and 15, were arrested on suspicion of causing grievous bodily harm. They were taken to an east London police station where they remain in custody.
"All involved were pupils at the school. Enquiries into the circumstances continue."
Anyone with information is asked to contact police via 101. To give information anonymously contact Crimestoppers on 0800 555 111 or visit crimestoppers-uk.org.