A boy has died and a second child was airlifted to hospital after they were struck by a vehicle during the school run.
Essex Police said a 23-year-old man has been arrested on suspicion of causing death by dangerous driving after the incident in the rural village of Stock on Friday morning.
The force said emergency services were called to Stock Road shortly after 8.20am following reports of a vehicle colliding with two children.
Despite the efforts of medics at the scene, one boy has died and the second child was taken to hospital for treatment.
A man has been arrested on suspicion of causing death by dangerous driving, causing serious injury by dangerous driving and driving whilst unfit through drink or drugs.
He remains in custody.
The two children are students at Mayflower High School in Billericay, around one-and-a-half miles away, its headteacher Damian Lee said in a letter to parents on Friday.
He wrote: “I am writing to regrettably inform you that two of our students were involved in a road traffic accident this morning.
“Sadly, one of the students passed away and the other student has been airlifted to hospital.
“The families of the students are being supported by a specialist police liaison team.
“We have informed staff and students through assemblies and are working with Essex County Council to look at the layers of support required during this time.”
Mr Lee said that further information would be communicated to people when it is available.
“We understand this is a very difficult time for our students,” he said, adding: “Our thoughts and prayers are with the families involved.”
Essex Police said Stock Road remains closed between School Lane and Honeypot Lane in Stock while they investigate.
Police carrying specialist equipment remained at the scene on Friday afternoon, with a large section of the road cordoned off with police tape.
Officers appeared to be looking at a red car and a green van, positioned a short walk from a bus stop.
The red car was later lifted on to the back of a truck to be taken from the scene.
Forensics officers in white suits worked at the scene, with at least two marked vehicles parked nearby.
Detective Inspector Mark Fraser, of the serious collision investigation unit, said: “This is quite clearly an incredibly tragic incident which will be felt by many people across the area, not least the families of the two young victims.
“Our role is to establish the circumstances which led up to this incident, which we will do meticulously, and I would ask people not to speculate, whether in person or online.
“I would also like to thank everyone who has already come forward to speak to us and would urge anyone who has information and not yet spoken to us to please come forward.”
Police have asked for anyone who witnessed the incident, has dashcam footage of it or has any information to get in touch with them.
They can call police on 101 citing crime incident 218 of November 3.
Published: by Radio NewsHub