A former Southmead man asked a mum if he could have sex with her daughter, aged 14.
But Gordon Walbridge's grotesque plan was abruptly scuppered when it turned out he had been talking to undercover police.
Walbridge was to face trial in December but the 50-year-old, formerly from Doncaster Road, pleaded guilty to arranging or facilitating a child sex offence.
Judge Martin Picton jailed him for 26 months.
The judge told the court: "It was absolutely horrific what he was planning to do, a bad example of this kind of case."
He told Walbridge to register as a sex offender for 10 years and barred him from working with children and vulnerable adults.
Kannan Siva, prosecuting, told Bristol Crown Court Walbridge was released from jail, for breaching a sexual harm prevention order, in May this year.
But in June he chatted online to who he thought was a "semi-literate" mum called Bella, and tried to arrange sex with her daughter Libby and sent a photo of his penis.
The mum and daughter turned out to be police and Walbridge was arrested in Weston-super-Mare.
He told police it had all been fantasy.
Sam Jones, defending, said it was a relatively short period of contact which was not directly with the supposed child.
Mr Jones said: "He recognizes that he has a problem and he has a sexual interest in girls of a certain age, and needs help to address those issues."
