A teenager was knocked unconscious on New Year’s Day as a gang robbed him in an underpass.
The 18-year-old was walking with ten friends when they saw three teenagers stood with BMX bikes.
One of the teens revealed a knife in the waistband of his trousers.
The victim was then punched and knocked unconscious for a few seconds. His friend was also attacked.
They quickly ran away after two of the offenders brought knives out from their clothing and stole cash.
The robbery took place in the H6 Childs Way underpass, in Davy Avenue, Knowlhill, leading into Loughton, at around 2.30am.
Two of the offenders are white, while the other is of mixed race. They are all in their late teens and all wore dark clothing and hooded tops.
The mixed race offender had a silver tooth on his upper left jaw. One of the other offenders wore a red hooded top under his black jacket.
Det Con Chris Bigg said: “I would appeal to anyone who recognises the man in this E-fit to contact police immediately by calling 101.
“I would also appeal to anyone else with any other information about the incident, no matter how insignificant you think it might be, to contact the police because your information could aid our investigation.
“I understand that some people do not feel comfortable speaking to the police so alternatively you can contact the independent charity Crimestoppers anonymously on 0800 555 111.
“No personal details are taken, information is not traced or recorded and you will not go to court.”