Police are appealing for information after two men were stabbed in a fight involving approximately 20 males.
Police and London Ambulance Service crews found the two stab victims in Regent Street, central London, at 3.20am today after the brawl in nearby Kingly Street.
The men, aged 27 and 31, were taken to hospital for non life-threatening injuries.
Forensics officers today scoured the scene in one of the capital's busiest shopping districts for clues.
Scotland Yard said officers were keeping an open mind about the motive and were studying CCTV.
A 27-year-old man has been arrested and is being questioned by officers.
Witnesses should contact the investigation team on 101 or call Crimestoppers anonymously on 0800 555 111.