A teacher accused of having sex with a teenager in the toilet of a plane was later blackmailed by another student, a court has heard.

Eleanor Wilson, 29, was sent a series of emails by one of her pupils, including an explicit photograph of his genitals, threatening to expose her alleged relationship with a teenage boy unless she had sex with him.

The boy contacted her after hearing about what allegedly happened on a flight back to the UK from an overseas camping trip in summer 2015.

Ms Wilson, then aged 26, is accused of kissing and cuddling a teenage student before “beckoning” him into the toilet cubicle, where she allegedly performed a sex act on him and then had intercourse.

Bristol Crown Court heard that within weeks of the pair returning from the trip, rumours had spread around the school that she was in a relationship with a student.

She was quizzed by the school’s headteacher and denied it, and without the name of the boy, the investigation could not continue.

By February 2016, Ms Wilson had begun receiving the anonymous emails, which threatened to tell the headteacher.

The first said: “I know about you and (the boy) and do you want that coming out?”

A second said: “Reply in 24 hours or it will slip out. We wouldn’t want that, would you.”

Within hours of the first message, Ms Wilson had told another teacher - which led to a police investigation - but she continued to receive emailed threats.

The blackmailer was soon identified and left the school, while Ms Wilson was suspended after admitting seeing the complainant outside of lessons, as he was a “screwed-up kid and she was just trying to help him”.

Earlier, the jury heard the boy deny he was infatuated with the defendant, insisting it was not a fantasy and that he was telling the truth.

The teenager, who cannot be named for legal reasons, said a “bond” developed between him and Ms Wilson while they were abroad.

She gave him her mobile number, which he saved on his phone as “Smurfette”.

Ms Wilson’s barrister suggested the plane would have been busy with teachers, pupils, other passengers and cabin crew, and what he claimed happened did not take place.

One pupil on the trip said he saw the boy sitting on Ms Wilson’s lap during the flight.

The witness, who had been ill during the journey due to food poisoning, described what he saw, but added: “I was completely dazed and unwell, and it was a dark cabin and I couldn’t see very well.”

The complainant, who said he was “reasonably intoxicated” after drinking red wine during the flight, had previously described how he and Ms Wilson allegedly had sex in the cubicle.

“When you came out of the toilet you were close enough together, making the risk that other staff and pupils and cabin staff could have seen you together,” said Anna Midgley, defending.

“It’s just not true. Nothing had happened.”

Ms Midgley also suggested another allegations of kissing, cuddling and holding hands, which allegedly occurred in the boy’s bedroom and at Tintern Abbey and the Ashton Court estate, were “fantasy”.

“Would you accept that you were infatuated with her when you got back from the trip, thinking about her all the time, wanting to be with her and not thinking clearly?” she asked.

“But she never approached you physically or sexually. That might be what you wanted, but it never happened.

“You were thinking about her a lot, and you were infatuated with her, and you had told your friends that things had happened that in fact had not happened.

“You had boasted to your friends and that led to rumours starting and someone started to blackmail her about that.

“Your parents started to question you and the school started to question you.

“At that point you couldn’t say none of this was true or that it didn’t happen and you said you had sex on an aeroplane because that’s what you told people.”

The boy, who was giving evidence from behind a screen, replied: “That is incorrect.”

Ms Midgley asked the complainant why the account he gave the police differed from what he allegedly told his friends.

“Did you tell your friends you had sex with Miss Wilson in Wales? Multiple times, twice or more, in Wales?” she asked.

“Did you tell your friends you had been sleeping alone with Miss Wilson in a tent on the trip? Did you tell them that you had sex with Miss Wilson in a car and there were stains on a front seat?

“It appears you told your friends these things and these were all part of your fantasy with Miss Wilson.”

The boy replied: “That’s incorrect.”

Ms 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.