A teacher accused of having sex with a student in the toilet of a plane as they returned from a school trip could face a retrial after a jury failed to reach a verdict.
The panel of four men and six women was discharged after deliberating for 10-and-a-half hours over three days in the trial of Eleanor Wilson at Bristol Crown Court.
Judge Peter Blair QC, the Recorder of Bristol, stopped the trial after the foreman informed him there was not a "realistic prospect" of reaching majority verdicts on any of the four charges of sexual activity with a child by a person in a position of trust that Wilson faced should they be given more time.
Judge Blair told the panel: "I am going to discharge you now from returning verdicts on this indictment but can I extend my grateful thanks to you on behalf of the court service for all the work you have been doing for the last three-and-a-half weeks.
"This happens from time to time. Every year I keep a spreadsheet of trials that I do and the outcomes that there are and each year there are quite a number of juries that have the same perfectly legitimate outcomes as this, what we call a hung jury.
"It is part of the system and you shouldn't in any way beat yourselves up about it."
Virginia Cornwall, prosecuting, asked for seven days for the Crown Prosecution Service to consider whether it wished to seek a retrial.
The 29-year-old was on trial accused of having drink-fuelled sexual intercourse with the teenager on a British Airways flight home from an overseas camping trip in August 2015.
It is alleged the teacher, then aged 26, kissed and cuddled the boy before "beckoning" him into the toilet where they allegedly had sex, with 6ft 2in Wilson perched on one leg, before returning to their seats.
She is also accused of seeing the boy outside of school where they allegedly kissed and cuddled on three separate occasions, after a meal at Nando's and trips to Tintern Abbey and Ashton Court.
Within weeks of the pair returning from the trip, rumours had spread around the school that Wilson was in a relationship with a student but when confronted by the head teacher she denied it, saying she was "horrified" at the accusation.
At the same time, Wilson discovered she was pregnant and went on to have an abortion, with prosecutors claiming the boy was the father.
The court heard their "clandestine" relationship was exposed months later when another pupil at the school tried to blackmail Wilson into having sex with him.
The Royal Navy Reservist said she formed a friendship with the boy because she had no friends of her own age she could confide in.
Wilson told the court the boy had imagined the incident in the toilet and also denied holding his hand and kissing him during time alone, insisting there was "no truth whatsoever" in the allegations.
She also accused her then partner Andrew Hall of being violent and controlling and not being ready to start a family with her.
The teenager, who bought Wilson flowers and chocolates, told the jury a bond developed between them and insisted his account was not fantasy and that he was telling the truth.
Mr Hall described their relationship as "dysfunctional" but denied he was "controlling", "jealous", "aggressive" and "physical" towards her.
Wilson, of The Rope Walk, Dursley, Gloucestershire, was released on unconditional bail.