Police were called to Hounslow Heath, near Staines Road, Hounslow, at just after 07:00hrs today, Sunday, 28 February to reports that a pedestrian and a van had been in collision, and subsequently to a large number of people fighting armed with knives and other weapons.
Police officers attended, and a man suffering injuries to his leg was found. He was taken to hospital by the London Ambulance Service.
The group had dispersed before the arrival of the police.
Two other men presented themselves to a hospital a short time later.
One is understood to have suffered a serious injury to his arm and the other had been stabbed.
Enquiries by officers have so far resulted in the arrested on three men in Hillingdon.
All were arrested on suspicion of violent disorder and remain in custody at this time.
An investigation has been launched by detectives from Hounslow CID.
Anyone with information is asked to call police on 101, or Crimestoppers anonymously on 0800-555-111.