Police are appealing for information and witnesses after a member of door staff at Home Nightclub in Lincoln was assaulted.
Two members of staff were removing a man from the landing of the third floor of the club on Park Street at around 1am on Saturday, February 28 when one of the doormen suffered a serious injury to his knee.
They were escorting him down a flight of stairs when the assault reportedly occurred.
Police say it was suggested that the man who was being removed also had an altercation with two Asian males in the toilets just prior to this incident.
Investigating officers are appealing for those men, and anyone who may have witnessed the incident, to come forward.
Anyone with any information is asked to contact Lincolnshire Police on 101 quoting incident number 30 of February 28.
Alternatively, people can contact the independent charity Crimestoppers anonymously on 0800 555 111.