A man approached two females and a male before exposing himself and performing a sex act in front of them at roughly 9pm on Pellat Grove on Thursday, March 2.
He then followed the group for a short while before eventually walking away, Scotland Yard said.
Officers are now releasing an e-fit image of a man they wish to identify and speak to in connection with the offence.
PC Lara Ridolfo, from the Met’s North Area Command, said: “Offences like this one are extremely serious and can have a significant and lasting impact on victims.
“I am grateful that the victims in this case came forward. Reporting crimes of this type is vital in order for us to identify and apprehend offenders.”
Anyone with information concerning the identity of the man pictured should call 101 or Tweet @MetCC quoting reference CAD 8272/02Mar.
To remain 100% anonymous call the independent charity Crimestoppers on 080 555 111.
