A primary school teacher has been found guilty of sexually abusing and murdering his 13-month-old adopted son, in a case described by detectives and prosecutors as among the most disturbing they have ever encountered.

Jurors at Preston Crown Court heard that baby Preston Davey died after months of escalating abuse at the hands of his adoptive father, 37-year-old teacher Jamie Varley, at the home he shared in Blackpool with his partner, 32-year-old financial sales manager, John McGowan-Fazakerley.

Preston had been placed into care shortly after his birth and spent his first 10 months with foster carers, where he was described as a happy and healthy child. In April 2023, following an assessment and approval process overseen by regional adoption agency Adoption Now and Oldham Council, he was placed with Varley and McGowan-Fazakerley.

Within weeks, medical staff and social workers were seeing signs that something was wrong. Preston was taken to Blackpool Victoria Hospital three times with suspicious bruising and injuries. Each time, the court heard, Varley and McGowan-Fazakerley offered explanations that were accepted at face value.

On the day of Preston’s death, Varley claimed the toddler had accidentally drowned in the bath after being left alone for a few minutes. But when doctors examined the child, his hair was dry, he was still wearing a nappy and there was no evidence he had swallowed water.

A Home Office post-mortem ruled out drowning and concluded that Preston died from acute upper airway obstruction caused by an object or objects forced into his mouth. The examination also revealed 40 separate injuries, including evidence of sexual assault.

During the eight-week trial, the jury was told that Preston had been routinely ill-treated, sexually abused and photographed. Varley was convicted of murder, multiple counts of assault by penetration, child cruelty, grievous bodily harm, sexual assault of a child and a series of offences relating to indecent images of a child. McGowan-Fazakerley was found guilty of allowing the death of a child, child cruelty and sexual assault of a child.

Detective Chief Inspector Andy Fallows, who led the investigation, described the pair as “pure evil” and said they had turned Preston’s short life into “a harrowing tale of misery and pain”.

Oldham Council confirmed that an independent Child Safeguarding Practice Review is under way to examine how agencies handled Preston’s case and whether warning signs were missed.