A secondary school teacher has today been found guilty of the shocking sexual abuse and murder of a baby he and his partner were adopting.Jamie Varley, 37, faces a life sentence over the tragic death of 13-month-old Preston Davey, who suffocated during sexual abuse.His partner John McGowan-Fazakerley, 32, a sales manager for a finance company, was also convicted of charges including causing or allowing Preston’s death and jointly participating in a sickening sexual assault.Prosecutors said it was one of the 'most shocking and horrific' cases they have ever dealt with. Perverted pair Varley and McGowan-Fazakerley were an outwardly respectable, middle-class couple living in an immaculate home in Blackpool.But they were found to have carried out what prosecutor Peter Wright KC described as ‘a litany of psychological and sexual ill-treatment’.Varley initially put his hand to his mouth as the jury foreman read out the verdicts - before collapsing and being sick in the dock. McGowan-Fazakerley stood motionless in the dock. Mr Wright said that instead of being given a loving home, over the near four-month period he was with the couple, Preston had been used as a ‘plaything’ to satisfy Varley’s desires.As the jury returned its verdicts, Preston's grandmother Debbie Davey called for social workers to be sacked after it emerged there were a string of missed chances to save him from harm.But Mrs Davey added: 'I'm so relieved, I'm happy it's all over.' It can now also be revealed Preston was the son of notorious murderer Sarah Davey, now 42, who as a 14-year-old murdered Lily Lilley, 71.Preston Davey died aged just 13 months after being suffocated and sexually assaulted Police mugshot of Jamie Varley, 37, found guilty of murdering Preston Davey John McGowan-Fazakerley has been convicted of allowing the abuse which led to tragedy Preston Davey with his mother Sarah Davey, who carried out a horrific crime as a teenager In what was described by a judge as an 'unspeakably wicked' crime, Davey and her friend Lisa Healey, then 15, befriended the grandmother of three and murdered her in her own home in Failsworth, Oldham, in 1998.Ms Lilley was brutally tortured - having shampoo squirted into her eyes, being cut with a knife and having a gag tied so tightly around her mouth that her dentures were forced down her throat.The pair then crammed her lifeless body into a bin and walked it through the streets of Failsworth before throwing it in the Rochdale Canal.After killing her, they made hundreds of calls from her phone and used her pension money to buy crisps and chocolate.Sarah Davey, first released from jail in 2013 but then in and out of prison due to breaking her release conditions, had her first child in 2019. The youngster is being brought up by her mother Debbie Davey, 66.Preston was born in June 2022 in Wythenshawe Hospital when Davey was back in prison - and was taken off her by social services just five days later and placed with foster parents.Mrs Davey wanted to formally adopt the boy but pulled out of the process due to a battle against breast cancer.She said social workers involved with the case ‘should be sacked’, adding: ‘Everyone involved with Preston is still working. That is not right.’Following a trial lasting over seven weeks, jurors at Preston Crown Court took 13 hours to find Varley guilty of murder, assault by penetration, sexual assault, causing grievous bodily harm and cruelty. The jury was made up of ten people - six women and four men - after two of its members, one woman and one man, were discharged last week. Varley, head of Year 11 at South Shore Academy in Blackpool, was also convicted of 14 counts of making or taking an indecent image and one count of sharing an indecent image.McGowan-Fazakerley was convicted of causing or allowing the death of a child, cruelty and sexual assault. Mr Wright said Preston had been ‘left at (Varley’s) mercy and paid with his life’ when he died on July 27, 2023.Rushed to Blackpool Victoria Hospital by Varley and McGowan-Fazakerley - with Varley putting on a theatrical show of hysterics, collapsing and crying ‘I’m going to hell’ - Preston was pronounced dead after just 50 minutes despite the best efforts of medical staff.Varley claimed Preston had drowned in the bath after he left him momentarily to get changed after having a shower.But suspicions were raised because he wasn’t wet and a post-mortem examination found no water in his lungs.Instead, a ‘sinister pathology’ was revealed, showing he died from ‘acute upper airways obstruction’, had bruising to his throat and serious internal injuries – as well as over 40 bruises and other injuries.The court heard Varley, alone with Preston, may have sexually assaulted Preston twice that afternoon, causing him to suffocate and have a seizure. The post mortem found his breathing may have been obstructed previously.Preston had been taken to hospital three times previously, with breathing difficulties on May 25, with an unexplained rash on June 30, when bruising was noted, and on July 6 with a broken elbow due to rough handling – resulting in the GBH charge.The court heard Varley told McGowan-Fazakerley that Preston also had a seizure on June 15, in messages sent to his partner when he was at home with the infant and McGowan-Fazakerley was flying back from a business trip.Mr Wright said: ‘The facts of the case point unerringly to the conclusion that Preston had been sexually abused and killed’.On the morning of his death, Preston was ‘in good health and uninjured’ – taken to Varley’s mother’s house where he was photographed playing happily on her knee.But the baby later twice went into ‘apparent respiratory distress’, the first episode filmed on Varley’s mobile phone camera, followed by his fatal collapse soon after, the court heard.Preston was driven to hospital when McGowan-Fazakerley returned from work in Manchester.