A cardiologist told an inquest it would have been “very unlikely” that paramedics could have saved a 14-year-old air cadet’s life if they had reached him earlier.

Professor Perry Elliot told Walthamstow Coroner’s Court yesterday he could only speculate on what led to the death of David Efemena who died on March 23 last year while on a weekend trip to the Bramley Defence Training Estate, Hampshire.

A post mortem examination revealed David had an anomalous coronary artery which, prof Elliot said was the “primary cause” of his death.

A congenital heart anomaly is a condition in which an artery is lodged between the two main valves, which compress it, reducing blood flow to the heart.

Prof Elliot said the condition would be exacerbated by exercise and was unable to explain why it would have had a fatal effect early in the morning, following eight hours rest.

He said: “This is why I think something must have happened to him before his heart stopped.”

Samantha Jones, who is representing the family, asked prof Elliott whether the outcome would have been different if the squadron leaders had reached David earlier.

He explained that David’s condition would have reduced the chance of paramedics successfully resuscitating him.

David had been diagnosed as a carrier of, mild blood condition, sickle cell trait, but Dr Andrew Will, haematologist, told the inquest the 10 hour escape and evasion exercise, he took part in would not have been “severe enough” to trigger a reaction.

Coroner Nadia Persaud said: “There is not enough evidence of the cause of death for it to be neglect.

“The most likely conclusions are going to be narrative and natural causes.”

The inquest continues on Monday.