A KENT school at the centre of a major pepper spray canister incident has reopened for lessons as normal.

But a group of police officers were on duty outside the entrance gates of Christ Church High School in Ashford on Friday as hundreds of pupils arrived, many accompanied by their parents.

The school saw chaotic scenes on Thursday afternoon when a noxious spray was set off resulting in 21 children going to hospital. Their symptoms included coughing, sore eyes and vomiting.

They were all sent home after being assessed and treated at Ashford's William Harvey Hospital. Another 35 pupils were treated at the scene.

Head teacher Catherine Barber said later: "It’s disappointing that one individual has had a negative impact on the smooth running of the school and interfered with and interrupted the learning of the majority of the students."

A boy of 12 was arrested on suspicion of possessing a pepper spray aerosol canister. He has since been released on police bail.

Tearful and confused pupils scurried in and out of the school gates after being evacuated from the building.

Parents, pupils, police, firefighters and paramedics gathered at the scene. The Kent Air Ambulance also attended.

Two men, one ageed 32 and the other aged 37, were arrested on suspicion of assaulting police in a separate incident at the school yesterday. They been released on bail while police make further enquiries.

Emergency services were called to the school, which is located in the Kingsnorth area of the town, shortly after 12.20pm.

The school has around 1,200 pupils ranging in age from 11 to 16.

Kent Fire and Rescue Service ventilated the area where the substance was released.