Detectives are appealing for information following an incident near Laindon Railway Station yesterday, Tuesday September 22.
Police were called at around 6.40pm to reports that a teenager had a serious head injury.
He was taken to hospital.
It is believed he was assaulted by a group of teenagers and young adults.
If anyone has any information, CCTV or dashcam footage please call 101 quoting incident 1079 of 22 September.