A member of staff was attacked during a confrontation involving three males at Pizza Hut on the Altrincham Retail Park last night.
The males had finished a meal at the restaurant when they attempted to leave without paying.
A confrontation ensued, during which a member of staff was attacked with a bike lock.
The employee suffered a hand injury and was taken to hospital, but the injury is not understood to be serious.
Police were called to the incident at around 9.20pm last night but no arrests have yet been made and enquiries are ongoing.
Anyone with any information about the attack should contact the police on 101 or contact the Crimestoppers anonymously on 0800 555 111.
