Armed police were called after a man "with a large knife" was seen near to a school in Sydenham at lunch time.
Officers were called at around 1.15pm on Thursday to reports of a man with a large knife in the vicinity of Dartmouth Road - near to Sydenham Sixth Form.
There were no reported injuries.
There have been no arrests.
Police enquiries are ongoing.
A spokesperson for the Metropolitan Police said they "do not believe the incident happened at the school but nearby".
The full statement said: "Police were called at 13:15hrs on Thursday, 29 September to reports of a man seen in possession of a large knife in the vicinity of Dartmouth Road, SE26.
"Officers, including firearms officers, attended.
"There were no reported injuries.
"There have been no arrests and enquiries continue."
We have approached Sydenham Sixth Form for more information.
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