The fight took place at an event held at Elm Park Primary School’s hall in Calbourne Avenue on Saturday (March 22) at around 9pm.
Two boys, 16 and 19, were stabbed and taken to hospital, with injuries thought not to be life-changing.
Victoria Morris, head of the school, has stated that this was a private hire birthday party event at the hall.
Following the attack, the school has decided to no longer allow the hall to be hired for events.
In a statement the headteacher said: “We were shocked to hear of a disturbance at a private birthday party in our hall over the weekend.
“This was a private hire and the people involved were not known to us.
“No one was injured on the school premises and we have carried out thorough checks to ensure that pupils could safely return to school this morning.”
Superintendent Simon Hutchinson said officers arrived in four minutes after being called and were “heavily outnumbered”.
Four officers were injured while dealing with the incident.
Three teenagers – two girls aged 14 and 17 and a 16-year-old boy – were arrested at the scene on suspicion of assaulting emergency workers and taken to an east London police station before being bailed.
Two further arrests – boys aged 15 and 17 – were arrested in Hornchurch the following day on suspicion of possessing an offensive weapon, and they have also been bailed pending further enquiries.
Ms Morris added: “We have successfully let our premises to the local community for years and have stringent protocols in place.
“We have written to local residents and parents to give them our assurances of this and we have also decided that the hall will no longer be let out for evening events.
“We had security in place and all fire exits, which were used by the young people to come into and leave the building, were clear.
“The incident is currently a police matter and we are helping with their enquiries.”
Anyone with information is asked to call police on 101 or message @MetCC on X, referencing 6940/22March.
