The video and images stretch over a period of three minutes and 12 seconds, with the child’s head and arms over the top horizontal bar of his cot and his neck resting on the bar.
His body is apparently partially suspended, his legs in a “frog like” position and the child seemingly asleep or unconscious.
“This is very unsafe and in my view dangerous,” Armour said.
“That’s going to inhibit your ability to breathe.”
In one still photograph, Preston’s head is in a slightly different position with fluid coming from his mouth.
Armour continued: “Preston’s tongue is protruding, it’s blue and also his lips appear blue, consistent with a lack of oxygen in the blood.”
Wright said: “In terms of a child in that position for that length of time, how safe or otherwise is such a position?”
Armour said: “This is a very prolonged period of time for a child to be in such an unsafe position.”
Four days later, at about 18:20 BST on 27 July 2023, the defendants rushed Preston unconscious from their home to Blackpool Victoria Hospital.
Medics worked for nearly an hour to resuscitate the child but could not save him.
Varley said he had left the child alone in the bath for three or four minutes before he returned and the baby was partially submerged.
Armour, who carried out the post-mortem examination, said people who drown often swallow water but she found no water in Preston’s stomach.
Armour concluded the cause of death was an upper airway obstruction, leading to Preston’s collapse by a deliberate act of smothering, or an object or objects inserted into his mouth.