Sentencing Locke, Judge Ticehurst snapped: “This has been a horrific experience for you? What do you think it was like for the two-year-old you watched being abused?”
He added: “You decided to talk to someone you thought was 12-years-old. You thought you were speaking to a 12-year-old and you were getting sexual gratification from it.
“How on earth do you explain something like that to your wife of 30 years? You should be disgusted with yourself.”
He sentenced Locke to 12 months in prison for attempting to incite a child into sexual activity, 18 months in prison for the Category A images, nine months in prison for the Category B images and six months in prison for the Category C images.
The sentence was suspended for two years to allow him to continue his work with the Lucy Faithfull Foundation.
He was also made the subject of a sexual harm prevention order for 10 years, ordered to sign the sex offenders register for the same period of time, and told to pay £550 in costs.