Nasar Ahmed took ill while in detention with other pupils at Bow School in Tower Hamlets, east London, on 10 November last year.

The teenager, who had a history of severe asthma and food allergies, suffered a reaction to milk in his tandoori chicken lunch and went into anaphylactic shock and complained he was having trouble breathing, his inquest heard.

He called for his inhaler before collapsing, turning blue and foaming at the mouth.

Staff at the school failed to administer his EpiPen, which may have saved his life, the coroner was told.

He died four days later at the Royal London Hospital from a brain injury which was brought on by the allergic reaction.

Coroner Mary Hassell on Friday returned a narrative verdict, saying: “The staff saw Nasar’s EpiPen and considered using it, but did not.

“If the EpiPen had been used promptly and Nasar had been administered adrenaline, there is a possibility but not a probability that this would have changed the outcome.”

Speaking outside the hearing at Poplar Coroner’s Court, Nasar’s mother Ferdousi Zaman told reporters: “If he has anaphylaxis I give him his EpiPen. They are first-aiders, they are more knowledgeable than me.

“They have failed their duty of care.”

Ms Hassell said she would be writing five Prevention of Future Death (PFD) reports, including to the school, Nasar’s GP, Barts Health NHS Trust and the London Ambulance Service, whose paramedic told staff over the phone not to give Nasar adrenaline before they arrived.

The inquest also heard that Nasar’s asthma had been inaccurately listed by the school nurse in his care plan as “mild to moderate” rather than “severe” and did not mention an EpiPen or using adrenaline to tackle his allergies.

In a statement, Bow School’s executive headteacher, Cath Smith, said: “We are all deeply saddened about this tragic incident and continue to offer our heartfelt sympathies to Nasar’s family.

“The safety of those in our care is, of course, our overriding concern, and following Nasar’s death we rigorously reviewed all of our safety procedures and are providing more training for staff across the board.

“We will now consider the advice from the coroner very carefully to see what further action we should take.”

Mrs Zaman described her son as a “jolly” boy who had lots of friends and had dreams of being a politician.

In a statement, the family added: “We strongly believe that if Nasar’s care plan had been completed correctly, if staff had been aware of the care plan and if it had been followed properly, including administering an EpiPen as soon as possible, that Nasar would be alive today.

“Following our painful loss of Nasar we hope that important lessons about the care of children suffering from asthma will be learnt and other lives saved.”

SKY NEWS