A 28-year-old man was attacked after a night out in Brighton.
The victim got into a cab at the taxi rank at the bottom of West Street in Brighton between 3am and 4am on Sunday (24 February).
Four men were already in the taxi which then headed east along the A259 coast road.
It stopped just before the Smugglers Rest pub in Peacehaven, Sussex Police said.
The victim, who lives in Newhaven, said that he was dragged from the taxi and attacked by the other four passengers.
PC Carlie Franks from Lewes Neighbourhood Response Team said: “The victim received cuts and bruises but did not want to go to hospital for treatment.
“We are keen to speak to the taxi driver and any witnesses who may have driven past and witnessed the incident.”
Anyone with information about the assault is asked to call Sussex Police on 101 or the independent charity Crimestoppers anonymously on 0800 555111.