The jury is being told that Dr Rosenthal, a consultant paediatrician, was instructed, based on his area of expertise, to consider Preston’s presentation both in life and at post mortem.
Dr Rosenthal concluded the cause of death should be ascribed to acute airways obstruction but says “the difficulty is what caused the obstruction”.
Dr Rosenthal watched the video recording at 4.45pm earlier that day, which Mr Varley filmed of Preston apparently not breathing.
He records: “Preston Davey, seemingly unconscious, no breaths in the first 15 seconds, Preston then starts to come round, has a small gasp and takes six or seven jerky breaths in the next 20 seconds. His lips became less blue as a result. His pupil size was medium but he is clearly vacant. His fingers twitched very slightly.
“The intensity of the cyanosis would mean the lungs had not functioned for at least 30 seconds. Very likely 45 seconds and possibly longer.”