Police are investigating after a 22-year-old's jaw was broken in an unprovoked assault at Latitude Festival.
The victim was approached by the suspect in the Sunrise Arena bar on Monday morning, around 12.35am and punched him in the face.
The offender wasn't known to the victim, who needed hospital treatment after the attack.
Suffolk police are asking anyone who witnessed the attack to come forward.
Latitude festival was held in Henham Park in Suffolk last weekend as a government test event with 40,000 people from across the country in attendance.