He was set upon by three louts in broad daylight on Wednesday following a dispute over a parking ticket.
Chilling footage shows the yellow-vested council worker on his hands and knees as the trio lay into him.
One of the mob holds the man by the collar as he repeatedly punches his face in Barking, East London.
The man, in his 40s, can be seen trying to shield his head before the attackers flee in a car.
Members of the public rushed to assist the warden shortly after the attack on Devon Road.
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He was taken to hospital with head and facial injuries but these are not life-threatening.
On Thursday, police arrested a 16-year-old boy, and two men, 26 and 49, on suspicion of ABH.
They remain in custody.
A Met Police spokesperson told The Sun: “Three males have been arrested following an assault on a council worker in Barking.
“We are aware of a video circulating online showing part of the incident, which happened at around 15:21hrs on Wednesday, 29 November in Devon Road, Barking.
“The victim, aged in his 40s, was working when he was kicked and punched to the ground following a dispute over a parking ticket.
“Following the incident an investigation was launched and three males – 16, 26 and 49, were arrested the next day on suspicion of ABH.
“They remain in custody at this time.”