Witnesses claimed the explosion happened after a rabbi threw a mobile phone on to the fire having given a speech warning about the dangers of smartphones and the negative impact on young minds.

Rabbi Osher Shapiro was at the front of the crowd when it was being lit. He said: “He [the local rabbi] did put a smartphone on the bonfire. It is wrong to suggest that it caused the problem. The phone did not cause the explosion. It went up very fast. It was just a metal frame covered in cotton wool and olive oil.

“There were hundreds of children there and a lot of them were at the front to get a better view. Luckily there were barriers. Without those, the injuries could have been worse.”

Rabbi Shapiro added: “Putting the phone on the fire is symbolic to show the negative impact they can have on young people.”

Explosion in Stamford Hill:
Paramedics rushed to treat those who were injured in the explosion (London Ambulance Service/Twitter)

Paramedics arrived in Ravensdale Road just before 9.30pm and treated 10 people at the scene. Those taken to hospital suffered minor burns and injuries. Hatzola, a Jewish volunteer emergency medical service, said it provided a “mega response team” and said “multiple patients were treated” at the scene.

Rachel Szwarc was at the event with her children aged four, six and eight. She said: “It went off like a bomb, people were screaming and shouting and tearing off their clothes because they were on fire. Everyone was trying to find their children.

“The children were all at the front to get a better view so they were the ones worst hit. My six-year-old had been at the front but luckily we went towards the back just before the fire was lit. We could see people with burns, it was very shocking.”

Community leader David Klein said seven children had been taken to hospital and all had been discharged. Organisers said that the phone thrown on to the fire did not have a battery. Lag BaOmer is a festive day corresponding  to the date of the death of Rabbi Shimon bar Yochai.