Graham Marples, 65, admitted the offence plus three counts of taking and making indecent images of the school-aged teenager.
He has been sent to prison for 18 months.
The court was told that another bus driver had admitted sexually assaulting the same girl on an earlier occasion and was currently on remand waiting to be sentenced.
Crown Advocate Fiona Russell told the court how the defendant had met the girl through his employment with Stagecoach.
She was a vulnerable person for a number of reasons and not just her age, having been diagnosed with autism and ADHD.
She had few friends and her mother said she had latched on to the defendant, who had offered comfort to her.
In a video interview recorded by police and used in evidence, she said the defendant had asked her to be friends with him on Facebook, though she did not use it.
He would ask her to travel on his bus with him around the island, gave her his rota cards so she would know when he was working, two necklaces, and a bank card which he encouraged her to spend with.
CCTV footage recovered from his bus from late January showed him kissing the girl on the lips, which constituted the sexual assault case. Her arm was resting on the cab door and he was also seen to pull it across his body and put her hand on his thigh.
On her birthday he gave her a bag of food on the bus. The interaction between the two that same day concerned a passenger who reported it to Stagecoach. By coincidence, that same day another bus driver with concerns of his own reported it to the company. He said that when he challenged Marples about what he had seen he had replied: ‘I don’t care what it looks like.’
Stagecoach reported the matter to police in early February and Marples was arrested 10 days later. He has been in custody ever since. It was also established that he had taken the girl for a meal at a local hotel without her parents’ permission or knowledge.
His electronic devices were seized and 11 images found, all screenshots he had taken during video calls he had with the girl while she was in a state of undress. Four images that were recovered across two devices contained inappropriate selfies that the girl had sent to him.
Marples gave largely no comment responses to questions in interview but did confirm his relationship with the girl.
The investigation led to the discovery of hundreds of calls between the two across various platforms.
He would start his messages by saying ‘good morning gorgeous’ and on one occasion the girl told him that she loved him. It was also established that he had tried to contact her after his arrest and had also asked his son to do so on his behalf.
Marples had some previous convictions but nothing similar and nothing for 30 years.
The court heard a victim impact statement that the girl’s mother had written on her daughter’s behalf, in which she explained how hard it had been to see her daughter deal with the consequences of what had happened. She said she had become ‘just a shell’ of the bubbly person she once was.
Defending, Advocate Fattorini said in terms of a sexual assault, Marples’ actions had been at the lower end of the scale. He had provided his pin numbers to police and the number of images were few and were never circulated.
His client would now have to leave the island and could expect to be subject to supervision when he returned to the UK. He had already spent eight months in custody and asked for the sentence to be back dated to when he was arrested.
Passing sentence, Lt-Bailiff Russell Finch said there aggravating factors in this case.
The defendant was aware that another bus driver had already sexually assaulted the girl before he did so himself and he described the relationship as ‘exploitative’. Marples had groomed and targeted a particularly vulnerable child in the course of his work in a public-facing role.
He said that Marples should be ashamed of himself and jailed him for 18 months for the sexual assault and six months, concurrent, on each of the other matters.
Lt-Bailiff Finch said the defendant would be subject to notification requirements for five years and an extended sentence licence for two years upon his release from prison. These were onerous and needed to bite, and the public should know that, he said.
The court wished to thank the bus passenger and the fellow bus driver who had raised the matter with Stagecoach.
A spokesman for Stagecoach said it was ‘appalled by the nature of the offences’.
‘Our thoughts are with the victim and all those affected by this case. We can confirm that the individual no longer works for Stagecoach.’
He added that the safety and wellbeing of its customers was an absolute priority.
‘We have robust recruitment and safeguarding procedures in place, including appropriate pre-employment checks for our drivers, and we take any concerns about the conduct of our employees extremely seriously.’