An expert medical witness said Rashan Charles’ life could have possibly been saved had CPR been started sooner.

However Jasmeet Soar, an intensive care consultant, said there were no obvious signs the 20-year-old was choking, and that officer BX47 and “witness one” did not think Rashan had stopped breathing – which would have been the two triggers to start it.

Rashan died in the early hours of July 22 last year, after he was chased by a police officer and wrestled to the ground in Yours Locally, Kingsland Road, Dalston.

A cellophane package containing paracetamol and caffeine was retrieved from his throat by a paramedic and he was taken to hospital. But he died an hour later because obstruction of his airways had led to cardiac arrest.

Mr Soar described to jurors at St Pancras Coroner’s Court what he could ascertain medically from the shop’s CCTV footage as well as from the body worn cameras worn by two police officers who can only be referred to as BX47 and BX48.

By the time BX47 put handcuffs on Rashan after a struggle on the ground, Mr Soar was “fairly confident” Rashan was unconscious.

At that point BX47 suspected Rashan might have put something in his mouth, and told him to “spit it out” eight times. He then lay him on his side, decided he was breathing, and called for back up. Mr Soar believed Rashan’s breathing, at that point, was not normal.

“You saw in the body worn video his eyes were bulging and his hands were reaching towards his face,” said senior coroner Mary Hassell. “They are obvious signs of breathing problems, but not necessarily airway obstruction,” said Mr Soar. “This is in retrospect and it was a dynamic 25 second incident. To me it’s obvious and I regularly manage airway and breathing problems. In the heat of the moment what’s obvious to the person standing back isn’t always obvious.”

Mr Soar said as well as it being difficult to ascertain whether someone is breathing it is also difficult to tell if someone is choking – and he could not see an “obvious point you would suspect choking” in the footage.

“I was at a dinner for the Resuscitation Council and someone did choke, and it took a while for people to notice. Then the person coughed up a piece of steak. It’s not always obvious,” he said. “The only obvious point is if the person is awake and conscious.”

The way BX47 tackled Rashan to the ground “clearly contributed” to the golf-ball sized packet getting lodged in his windpipe, Mr Soar said.

While the usual method to remove an object from a windpipe is for someone to cough it up themselves or use the Heimlich manoeuvre, once someone has fallen unconscious medical guidelines recommend CPR to dislodge the object.

Mr Soar explained how once a foreign object blocks the airway, you can’t breathe, you lose consciousness and after a few minutes your heart stops beating – cardiac arrest.

He believes Rashan could have been in cardiac arrest by the time officer BX48 arrived on the scene and turned Rashan onto his back, before starting CPR.

By the time the paramedic arrives a few minutes later monitoring equipment showed his heart had definitely stopped beating.

It then took the medic more than seven minutes to remove the package from Rashan’s airpipe, using suction and then pulling it out with forceps at 2am.

“Are you able to say, if you were there and you saw all this happen what would be the way you would treat Rashan medically?” asked Ms Hasell.

“I would uncuff him and roll him onto his back and open his airways,” said Mr Soar. “But as soon as I worried he was bad, I’d have called 999 and started CPR.”

He added: “Even if you do this all the time your heart rate goes through the roof. It’s a stressful situation when someone looks like they are dying in front of you. Everyone panics – even me.

“The guidelines call it basic life support, but anyone who understands realises there’s nothing basic about it, because there are quite a lot of decisions to make.”