A man needed 15 stitches after being stabbed in the leg outside a 21st birthday party in Leatherhead, Surrey.
Police are appealing for anyone who was at the party at the town's working men's club to contact them.
A 22-year-old man at the event was stabbed in the thigh outside the club in an apparently unprovoked attack and needed 15 stitches to the wound.
A fight had broken out between two men when a third man stabbed the victim just before 0100 GMT on 1 February.
The man ran back inside the club after the attack where he lost consciousness.
Police described the man responsible for the assault as white, about 5 ft 11 in tall, of stocky build and with short black hair.
Anyone who was in the area at the time of the incident should contact Surrey Police.