A sex pervert was locked up after getting caught in a "honey trap" when vigilantes invented the identity of a 12-year-old girl.
Christopher Cannon, 28, was faced with two members of campaign group Silent Justice at Hucknall Railway Station, where he had agreed to meet the child.
Nottingham Crown Court was told that the girl was said to be living unhappily with her grandmother in Sheffield. These details were posted on a website and Cannon began swapping messages within minutes.
A prison term of three years four months was imposed on Cannon of Goodall Crescent, Hucknall. He was put on the Sex Offenders' Register indefinitely.
Judge Stuart Rafferty QC said: "It is quite plain in July you began to think in a way no right minded person would even dream of.
"You were communicating with a person you believed to be 12 about sexual matters, encouraging that child to run away and live with you.
"If this child had been real and you had sexual intercourse with that child and carried out your warped fantasies, the sentence would be in double figures, despite the fact you have no previous convictions.
"Having been led into a honey trap by members of the public, you did not attempt to escape."
Matthew Lowe, prosecuting, said the group posted a written profile of the child on an internet site. It took "no more than nine minutes before this defendant made contact, believing it to be a girl of 12."
Mr Lowe told the court: "Almost from the outset, the defendant turned that conversation to sexual matters.
"He told her he wanted photographs of her wearing a nappy. If she agreed, he said it would be their secret and nobody else would know about it."
Cannon suggested they could have sex. When he received a message saying the girl was worried about getting pregnant, he offered to use condoms. He mentioned other sexual activity with the girl.
"He said he would allow her to buy sweets," said Mr Lowe. Arrangements were made to meet the girl at the railway station on July 23. Instead, he was confronted by two members of Silent Justice.
Police were called and he declined to answer questions. When officers searched his home, they found condoms and "used nappies."
Felicity Campbell, mitigating, said Cannon had the condoms because he was in a "long distance relationship" with a woman. He had "a sexual fetish" regarding nappies.
She suggested that Cannon could be given a suspended prison sentence and ordered to attend a course to prevent a repeat of the offences.
Miss Campbell added: "He does identify as someone who is open to rehabilitation and to work on a programme."
Cannon admitted inciting a girl under 13 to sexual activity; attempted grooming; attempted sexual communication.