A woman suffered a a fractured cheek bone in a pub garden earlier this month.
The victim, aged in her 20s, was in the rear garden of The Olde Leather Bottle, in Leverstock Green Road, when the incident happened between 9.30pm and 10pm on Wednesday, July 11.
She tried to intervene in a dispute and was hit in the face.
PC Natalie Williams said: “There were a number of people in the garden at the time and I am appealing for anyone who saw the incident, or events leading up to it, to please contact us.”
Call Herts Police on 101, quoting crime reference 41/16937/18, or visit https://www.herts.police.uk/Report.