The incident happened outside the Cathedral Hotel, in Milford Street, at around 2.15am on 20/02/22.
The victim, a man in his 20s, was walking home from a night out when he helped a woman who was trying to break up two other men who were arguing.
However, one of the men assaulted him resulting in facial injuries, which required treatment.
CID South have released two CCTV images of a man they would like to speak to in connection with this assault.
They would also like to speak to the man and woman who were also there at the time. The second man is described as white, aged around 18, and wearing a green checked shirt. The woman was also white, and around the same age, with long black hair.
Detective Constable Lou Poole, from Salisbury CID, said: “This was a nasty, unprovoked assault on a man who had simply tried to assist a woman who asked him to help intervene in another argument.
“He was left with serious injuries and we need to identify all three of these people who will hopefully be able to assist with our enquiries.”
- Anyone with information should call CID South on 101, quoting crime reference 54220018152. Alternatively you can call Crimestoppers anonymously on 0800 555111.