A St John Ambulance leader and full-time paramedic who enticed a 15 year old girl in to his bed was jailed for 40 months.
David Harley "groomed" the girl through internet text chat, eventually persuading her to send him a photo of her breasts, Stafford crown court heard.
Just days later, she went round to his house in Stafford, told her mother she was staying with a friend and spent the night with him.
Mr Paul Farrow, prosecuting, said the defendant and the girl drank half a bottle of vodka before engaging in sexual acts, including oral sex.
At the time, Harley was on probation by the St John Ambulance following complaints about his conduct towards one of his own girl cadets.
Mr Farrow said Harley was cadet leader in Stafford for the volunteer body, whose child protection officer had drawn up an "action plan" for him with guidelines about contact with young people. After being suspended, he was allowed back on probation.
Harley, aged 25, of Salt Road, Stafford admitted causing a child to engage in sexual activity, sexual activity with the 15 year old and a separate offence of taking indecent photographs of a 17 year old girl.
The court heard that Harley was in a legitimate sexual relationship with the 17 year old, a St John cadet. But while it was legal for him to have sexual intercourse with her, the law now banned him from taking photos of their sexual activity.
Mr Farrow said Harley began MSN text conversations with the 15 year old in April 2008. By August that year, the conversations became sexual and she complied with his requests for a picture of her breasts. He sent her a picture of his private parts, at her request.
A few days later, he asked her to come round to his house - and to tell no-one about it. At the house she rang her mom and asked if she could stay over at a friend's house.
"The defendant told her he loved her wanted to be with her. he spent the night with her, performing sexual acts on each other."
The offences did not come to light until months later when the girl's mother found the girl's MSN messages on the computer.
When questioned by the police, Harley described the sending of the photos as "harmless fun", but admitted that after being seen by the St John child protection officer, he knew he shouldn't be doing it.
In a victim impact statement, the girl said she felt "ashamed and humiliated, confused and angry about what had happened to her."
Miss Joanna Clark, defending, said Harley maintained he was not deliberately "grooming" the girl.
"She was making it clear she was sexually attracted to him, he felt flattered by her attention.
"She turned up at his address. It was his duty not to let her in and, when she tried to initiate sexual contact to end it.
"he has lost his job as a paramedic with Ambuline. It was his lifelong dream to be a paramedic. He knows he will never be able to work in that role again."
But Judge John Maxwell said he "completely rejected" Harley's mitigation.
"To suggest she is to blame for what happened is totally unacceptable.
Of course a girl of 15 may feel infatuated, but the age gap means that does not constitute any mitigation.
"At the time this was going on you were in a relationship with a young lady who was in the St John Ambulance, a cadet. you had agreed with this 17 year old not only would you have sex together, but that you and she would take photos of your sexual activities. The photographs were taken when she was 17 and were therefore illegal. She says she had no idea it was illegal and I am prepared to accept you had no idea."
Along with the jail sentence, Harley was ordered to register as a sex offender for life, banned from working with children, also for life and made subject to a Sexual Offences Prevention Order indefinitely which includes bans on him striking up friendships with under 18s or having under 18s in his house.
"He must never again work with children. The work for St John Ambulance is closed for ever," said the judge.
