Detectives in Southwark are appealing for information following a number of incidents where a man has exposed himself to children aged as young as 6.
The suspect is described as being around 20 years old and was riding a mountain bike during these offences.
The first incident was reported on 30 August. Police say that the victims were aged between 6 and 13.
"This type of incident is worrying and upsetting for both victims and families," says Detective Constable Andy Flitney from Southwark's community safety unit.
"We urgently need to speak to anybody who has information that may help to identify and arrest the suspect responsible".
If you have seen anything suspicious or have any information please contact DC Flitney on 020 7232 6195.