A medical expert has said police use of CS spray on a young father who died after an arrest attempt “could in theory” have contributed to his death.

Edir Da Costa, also known as Edson, of Wilton Way, Hackney, was stopped by police on the Woodcocks estate in Beckton on June 15, 2017.

Four officers tried to handcuff him with one aiming CS gas at his face. Edson later became unresponsive with wraps of class-A drugs found in his mouth.

The 25-year-old car trader died in hospital six days later.

Prof Jerry Nolan, a consultant in anaesthesia and intensive care medicine, said the most likely possibility was that Edson had already gone into cardiac arrest by the time he was placed in the recovery position, minutes after getting out of the Mercedes he and the group were stopped in.

Appearing at Walthamstow Coroner's Court on Wednesday, Prof Nolan said the most likely possibility was that Edson was already experiencing a cardiac arrest between getting out of the Mercedes the group were stopped in and his being placed in the recovery position minutes later.

He agreed with the cause of death given by the pathologist that Edson's death was due to a lack of oxygen caused by a plastic bag containing wraps of drugs getting lodged in his throat.

Prof Nolan explained it would have been difficult to tell whether Edson's struggles during the arrest attempt were the result of a bid to escape or a sign he was struggling to breathe.

"It would be difficult for individuals to make that call during these circumstances," he said.

Edson would also have found it hard to show he was choking because his hands weren't free and if his airway was completely blocked he would have been unable to make a sound, the jury heard.

And his ability to breathe would have been difficult because he was lying on the ground, although he was put into the recovery position relatively quickly.

On the general use of CS spray, with which Edson was targeted, Prof Nolan said: "It's theoretically possible [it] can make airway obstruction worse."

But he added it was also 'entirely possible' it could alleviate an obstruction if a person was able to cough.

On whether the officers' use of CS spray on Edson at close range could have contributed to his death, Prof Nolan said: "It could, in theory, have contributed."

A CT scan later carried out at hospital found Edson suffered severe brain damage which suggested to Prof Nolan that the young father had gone without oxygen for a 'very long period of time' before his airway was cleared.

On whether Edson's life could have been saved, Prof Nolan said: "The only way Mr Da Costa would have been saved is if it had been recognised he had an airway obstruction and it was dealt with before he lost consciousness and had cardio respiratory arrest.

"On this occasion, the first sign there was a major problem was when Mr Da Costa stopped struggling. That would have been the first opportunity for someone to have had a realistic chance of thinking, 'Has something gone horribly wrong?'"

But, the court heard, without specialist medical equipment, it would have been difficult to remove the bag from Edson's airway.

Asked about police efforts to save him, Prof Nolan said: "The CPR done by the officers was exceptionally good. They did everything they possibly could."

But efforts by police and paramedics to get air into Edson's lungs would have been hampered by the bag which was so far down Edson's throat it would have been difficult to spot.

He added that the use of restraint might have contributed to Edson's death if it included use of pressure on his neck. But senior coroner, Nadia Persaud, said the jury had not been presented with any evidence of that.

Prof Nolan said: "If freed from restraint and encouraged to cough up the bags of wraps, in my opinion, he would have survived."

However, Prof Nolan agreed after John Begs QC, representing the Met, said: "The only prospect of saving this young man's life would have been if there was a trained paramedic at the scene at the time [of the arrest attempt]. But in the real world that's not going to happen."

The inquest continues.