A science teacher had sex with a pupil in the toilets of a passenger jet after they grew close on an overseas school camping trip, a court heard.
Eleanor Wilson, 29, is accused of fondling the boy as she sat next to him on the overnight flight before beckoning him into the cubicle and performing a sex act on him.
They then allegedly had full sex in the cubicle – with 6ft 2in Wilson perched on one leg – before going back to their seats.
Prosecutors claim that Wilson later told the boy she was pregnant with his child but she would have an abortion.
Bristol Crown Court heard their “clandestine” relationship was exposed when another pupil at the unnamed school tried to blackmail Wilson into having sex with him.
Jurors were told that the defendant, who was then aged 26, and the boy had both been drinking during the flight back to the UK in the summer of 2015.
They had been part of a group of staff and pupils on the school trip and Wilson and the boy, who cannot be identified for legal reasons, had spent a lot of time together.
Virginia Cornwall, prosecuting, told the court: “It was the circumstances in which the two interacted on that trip that led to an erosion of boundaries and it was her responsibility, the Crown say, as the adult, to ensure there was no erosion of boundaries.
“She was a 26-year-old woman and he was a teenage boy. It was her choice to be with him. There were a lot of night time chats where others had gone off to bed.
“He was being treated on a par, an equal basis, as if an adult.”
Miss Cornwall said the pair had been drinking on the flight home and after kissing him and fondling him, she beckoned him into the toilet, where they had sex.
“Having had sex they went back to their seats. It was a secret between them.”
Miss Cornwall described Wilson as a “bright and competent” teacher who was “highly regarded” by colleagues.
“She was a woman who had a different side to her, one that those who knew her professionally didn’t see,” she said.
“She was a woman having a clandestine relationship with a pupil. She is a risk taker.”
After returning home, their relationship continued, with Wilson and the teenager going for a meal in Nando’s with others from the trip and also having days out alone together.
The court heard that the boy bought Wilson a bunch of flowers and chocolates, she gave him a lift home and he showed her his bedroom where they kissed.
They also allegedly had days out together at Tintern Abbey and Ashton Court, going for pub meals and drinking pints of cider together.
The jury was told they had swapped mobile phone numbers and Wilson rang him while she was on holiday in Italy with her boyfriend.
The boy’s father noticed his son’s behaviour had changed and he talked “incessantly” about the defendant and said he was going to split up with his girlfriend.
The teenager had told friends about the relationship but sworn them to secrecy, and when the pair returned to the school for the start of the new academic year, rumours circulated.
Wilson was spoken to by the school’s head and deputy, but denied it and “appeared shocked”, Miss Cornwall said.
She later allegedly told the boy she was pregnant by him but would go on to have an abortion.
In February 2016, Wilson told a deputy head she was being blackmailed by another student and the police began an investigation, which led to her resigning.
“He started emailing Eleanor Wilson, threatening to expose her for what happened between her and the boy unless she had sex with him,” Miss Cornwall said.
“She engaged with this blackmail instead of going immediately to a superior. She tried to deal with it herself.
“You might think it is not the usual reaction. She tried to sit on it and cover it up.”
During police interviews, Wilson denied that any sexual activity had taken place, describing the boy’s claims as “pure fantasy”.
She said there was a “lowering of the boundaries” because of her “pastoral interest” in the boy.
“She said she shouldn’t have gone as far as she did. There was a bit of flirtation but it had gone no further,” Miss Cornwall said.
“She confided in him about the pregnancy because she was isolated, lonely and he was a friend.
“She does accept there was some inappropriate contact outside of school but nothing sexual happened. It was out of concern to him and loneliness.”
Wilson, of The Rope Walk, Dursley, Gloucestershire, denies four charges of sexual activity with a child by a person in a position of trust.
The trial continues.