Officers from the Metropolitan Police were called at 7.05pm on September 21 with reports of a person believed to be in possession of a knife.
They were dispatched to The Brewery in Waterloo Road.
At the scene, emergency responders located four teenagers and a toy machete.
All four were arrested on suspicion of affray and were taken to an east London police station.
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There were no injuries reported.
A large police presence was seen in Romford on September 21, with social media users reporting that police vehicles had blocked off a section of South Street.
Images shared on Facebook showed several police officers outside Romford Station in South Street, which is less than a five minutes’ walk to The Brewery.