A man was deliberately run over before a large armed fight broke out at Hounslow Heath, police believe.
Two people remain in hospital following the mass brawl in Staines Road, Hounslow, on Sunday (February 28) morning, in which one man was stabbed.
Police have now arrested seven people in connection with the fight, two of whom have been charged .
Detective Sergeant Dean Purvis, of Hounslow CID, said: "We believe that the incident started in the car park of the car boot sale whereby a fight took place before a person was run over deliberately, suffering serious injuries in the form of a broken leg, a fractured skull and a stab wound.
"Shortly after, three vehicles were involved in a road traffic collision on Staines Road, Hounslow.
"The occupants of the vehicles then engaged in a fight whereby a number of weapons were used.
"During the fight a male suffered a serious injury/wound to his arm, another male suffered minor stab wounds and an unknown male suffered a facial injury."
Seven people now arrested
Police said they were called to the scene just after 7am to reports a pedestrian and a van had been in collision and that a large number of people had subsequently been involved in a fight armed with knives and other weapons.
The fight had broken up by the time officers arrived, but a 22-year-old man was found with leg injuries and taken to hospital by London Ambulance Service.
Four more men, aged 17, 11, 39 and 42, presented themselves at a hospital a short time later. One of the men had a serious injury to his arm, said police, and another had been stabbed.
Seven people were arrested: six for violent disorder and one for assisting an offender.
Two people have been charged, three have been bailed pending further enquiries and two remain in hospital under arrest .
The organisers of the car boot sale in the Hounslow Heath car park, near to where the fight broke out, have issued a statement on their website saying the fight did not break out at the event.
"We are unaware who was involved. The matter is now being investigated by the police," they added.
More police officers will patrol the area of the car boot sale on Thursday (March 3) and Sunday (March 6), however.
Anyone with information is asked to call Hounslow CID on 020 8247 6160 or Crimestoppers, anonymously, on 0800 555111.