Four men have been granted bail after a fight broke out an Bedfont Green fun fair , leaving one man critically injured.
Four men, aged 22, 23, 35 and 37, were arrested on suspicion of violent disorder in connection with the incident which shook visitors.
A Metropolitan Police spokesperson said: "They were taken to west London police stations and have since been bailed to a date in early August pending further enquiries."
Emergency services were called to the Hounslow location at around 6.15pm on Sunday (June 19) to reports of a fight.
London Air Ambulance confirmed they found a man, aged mid-30s, with injuries, who was taken to a west London hospital where he remains in a critical condition.
They told getwestlondon: "Our advanced trauma team was dispatched via aircraft by the London Ambulance Service at 6.41pm on Sunday to reports of an assault in Hounslow."
The news came as a shock to the community, many of whom had either visited, or planned to visit the fair with their younger children.
Detectives from Hounslow CID are investigating.
Anyone with information is asked to call Hounslow CID on the police emergency line 101.
