An investigation was launched after police were called at 2.54pm on Tuesday, 23 March following reports of a stabbing on High View Parade, Ilford.
Officers and London Ambulance Service attended the scene where they found a 15-years-old boy suffering from several stab wounds to his abdomen and torso. He was taken to hospital where he remains in a critical, but stable condition.
Witnesses reported seeing a male wearing a balaclava get out of a red Range Rover Evoque prior to the attack.
Three males, aged 18, 16 and 15 were arrested on suspicion of grievous bodily harm (GBH) and all have since been released under investigation.
Detectives from East Area CID are leading the investigating.
Detective Sergeant Tricia-Gay Crosdale, said: “A 15-year-old boy was attacked in broad daylight in a busy area of Ilford and he still remains in hospital. I’m confident that someone saw something and we need hear from you. This was a violent attack and the people who orchestrated this attack are still in the community.
“We need to know who the people were getting out of a red car which we believe is a Range Rover Evoque. Did you see it around High View Parade on March 23? Do you know who owns this vehicle? Any information could be vital in binging those responsible to justice.”
Any witnesses or anyone with any information is asked to call police on 101 or contact via Twitter @MetCC. Please quote CAD4541/23MAR.