A suspect allegedly threatened someone with a knife and demanded their watch on Lower Road, Rotherhithe.
After receiving reports on an attempted robbery, police were called the scene at around 12.25pm on Tuesday, January 30.
Officers responded within five minutes but said the suspect had left the scene when they arrived.
No arrests have been made and enquiries are ongoing.
A Met Police spokesperson said: “We were called at about 12:25hrs on Tuesday, 30 January to reports of an attempted robbery in the vicinity of Lower Road and Rotherhithe New Road, SE16.
“Officers responded within five minutes.
“The suspect allegedly demanded the victims watch and threatened him with a knife. The victim was not injured as a result of the incident.
“The suspect had left the scene prior to police arrival.
“No arrests have been made and enquiries are ongoing.”