Darlington's stepdaughter Jade Walsh was 16 when a secret camera was discovered in her bedroom.
When Jade's mother Caroline questioned the presence of the camera, Darlington claimed he had installed it to "check she was not being sexually active with any boyfriends that might come round."
A camera had also been installed in the family bathroom which Darlington used to spy on Jade in various states of undress.
Following suspicions from Caroline, police were alerted to Darlington's stash of indecent images in the couple's home in Rhyl, North Wales.
38 of the nearly 100,000 images were of Jade and police officers also discovered 365 videos of children during their searches.
Admitting that she is now fearful of people, Jade opened up about the experience in a victim impact statement read out in court.
Judge Rhys Rowlands wholly condemned Darlington's behaviour, calling it 'serious and disturbing'.
Commenting on the case, the judge said: "In any view this was utter depraved on your part. You treated her as your daughter and she treated you as her father. I'm dealing with a very bad breach of trust."
Darlington has been jailed for 14 months, ordered to sign the sex offenders register and has been made subject to a 10 year sexual offences prevention order.
