Police were called to disperse up to 200 teenagers denied entry to an under-18 event at a bar.
The night at Loco Lounge in Station Road, Chingford, was heavily publicised on social networks and within 45 minutes of opening, the venue had reached its maximum capacity of 180 people.
But young people, some of whom police described as “possibly intoxicated”, congregated outside the venue.
Police were called to the bar at 9:20pm following complaints of a large number of young people causing a nuisance in the street.
They started to disperse when officers arrived and no arrests were made.
Battista Battaglia, owner of Italian restaurant L'Artista in Station Road said he had to lock his doors to prevent further disturbance.
He said: "It was a big nuisance last night. The bar had reached its capacity and wasn't letting anymore people in so they congregated outside. I saw kids running around and shouting.
"We had to lock our main door during service to stop them coming in trying to use the toilet and being disruptive.
"They try very hard to keep it in control and it is a massive improvement on the previous owners, but I think the bouncers were overwhelmed last night.”
A statement released by Loco Lounge said: "We can confirm we hired out the venue to a promotions company for an under 18 event. The number that turned up to the event was over the capacity of the venue.
"Due to health and safety, we had to restrict the numbers. Once we reached capacity around 8:45pm, we asked them to contact their parents and make their way home safely and quietly.
"We only allowed five people at a time onto the decking outside and at the end of the night; we made sure everyone got home safely."