Three people were knocked down by a car as up to 60 fought in the street outside a celebrity hangout, police say.
Violence flared in Brentwood High Street, outside the Sugar Hut nightclub early on Sunday morning.
During the brawl, two men and a woman were knocked down by a car, which was then driven away from the scene, Essex Police said.
Two of the victims were seriously injured and all three were rushed to hospital, police said.
Taxi driver John Rolfe told the Standard he saw the fight break out and was the first to dial 999.
The 72-year-old who has worked in the area for 14 years described how he saw two men and a woman hurled to the ground as 50 to 60 people brawled in the street.
Mr Rolfe said: “All of a sudden a lot of people left the club and began fighting in the street.
“One man was knocked down and looked to be unconscious then another was knocked to the floor and looked to be seriously hurt.
“The club’s security intervened but there were just too many people for them to control.”
Mr Rolfe added that he picked up a customer who said he had “been forced to jump out of the way of a black Range Rover”.
He said: “I picked up a customer who said a black Range Rover have mowed into people on the pavement.
“He said he had to jump out of the way or he would have been knocked down.”
Actor Nick Nevern tweeted: “Wanna wish everyone who suffered injury outside the @sugarhut tonight the best of wishes... truly scary scenes.”
Mick Norcrosse, owner of the club, told EssexLive: "I can't say too much as it's an ongoing police incident.
“All I can say is that the club was closed when it happened, so there'd have been hundreds of people out on the street at the time.”
One person wrote on Facebook: “Huge riot kicked off after the Sugar Hut closed tonight.
“Lots of people hurt and during that an eye witness told me he saw a black Range Rover Sport mow down three people right in front of him.
“He himself had to jump out of the way to avoid being mowed down.”
Sugar Hut was made famous by hit TV show The Only Way Is Essex and is regularly visited by members of the cast.
A spokesman for Essex Police said: "Police are appealing for witnesses following a disturbance in High Street, Brentwood, at around 3.10am today, Sunday, March 2.
"We received calls about a fight between a large group of people outside the Sugar Hut night club.
"Two men and one woman were then struck by a vehicle, which drove away from the scene.
"They have all been taken to hospital, two with serious injuries."
Police are appealing to anyone who witnessed or filmed the incident on their phones to get in contact with Brentwood CID on 101.
Alternatively, call Crimestoppers on 0800 555 111.