A school has warned pupils not to share online logins after strangers hacked into lessons and allegedly made sexual threats - with one man reportedly exposing himself on camera.

The headteacher sent a furious letter to parents after pupils leaked the Microsoft Teams logins for online lessons leading to two strangers 'joining' the lessons last week.

Chris Thomas, headteacher at Lynch Hill Enterprise Academy in Slough, blasted the pupils after one of the intruders made 'threatening sexual comments as to what they were going to do to the teacher'.

He warned that other schools had reported incidents of men exposing themselves to classrooms - but this didn't happen at his school.

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The secondary school head threatened to halt live lessons altogether if pupils continued to flout the rules and share lesson log in access with others.

Thames Valley Police is investigating and child welfare charities have branded the intrusions 'disgraceful, obscene and unlawful'.

A family member of one child at the school in Slough said kids were sharing the login details on Snapchat.

In his letter to parents, Mr Thomas said: "I am writing to say how saddened I am by two very unpleasant incidents that happened last week, caused by the stupidity of students at school who chose to ignore the guidance sent to them about behaviour in these lessons and shared the link with students outside school.

"This has led to two crimes being committed and the police are now investigating both.

Lynch Hill Enterprise Academy in Slough

"I am pleased to say that one of the 'intruders' has been identified and I have been in contact with his headteacher and will be guided now by the police investigation.

"I am hopeful that the police will now be able to identify the second 'intruder' using their IT specialist team.

"The crime in both cases was 'Malicious communication with threats to the safety and wellbeing of a person' and the person involved will end up with a criminal record which will stay with them for the rest of their life.

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"I have emailed your son or daughter to make it very clear, that they must not share the login details for any lesson, nor should they allow anyone else into the lesson by inviting them into their room whilst the lesson is happening.

"It is a very dangerous thing to do and the police are taking swift action to deal with anybody who is involved.

"Other schools have reported incidents of men exposing themselves to classrooms.

"The only way that this can happen is if a student in the lesson shares their log-in details.

"I really do not want to stop live teaching because it is so important to your child's education and future life, but I am not going to allow my teachers to have to experience such unpleasant and upsetting situations, so if it happens again, I will reconsider whether we continue with live teaching.

"I would ask, once again, for your support in ensuring that your children understand the serious nature of this behaviour."

A sibling of a student at the school said: "I was shocked to hear that there had been security breaches within the live lessons. It worried me that from one silly child giving out their information to access the live online lessons all the other children could be put in danger.

Pupils have been told to note share the login details

Pupils have been told to note share the login details

"Fortunately, my sister did not have to witness any of this shocking behaviour, but to think she could have seen a man exposing himself or witness threatening behaviour scares me.

"The reality is this isn't just a couple of children. I've seen a lot of Snapchat stories with this information being posted.

"Children are posting their log in details on social media and they clearly don't realise the danger they are putting themselves and others around them in.

"Some of the children that are posting their login details on social media, the accounts aren't even private, so literally anyone can see the information and access the lessons.

"It's beyond worrying and something needs to be done to change this."

A spokesperson for Slough Council said: "In the first incident the intruder caused a bit of disruption, but the second made threatening sexual comments as to what they were going to do to the teacher."

Thames Valley Police confirmed officers have received a report and an investigation is ongoing.

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Andy Burrows, head of child safety online policy at the NSPCC, said: "These are concerning reports that will have been incredibly upsetting for both the pupils and teachers involved.

"While schools are making incredible efforts to provide remote learning in a safe environment, it's important to restate the vital precautions that can lessen the risks - including not sharing full meeting details and passwords on social media and only providing them to people you trust.

"Tech firms providing video conferencing services must ensure they take every step possible to minimise risks to children."

Tony Neate, CEO at Get Safe Online, said: "This incident that has happened to children and their teacher in a school environment is disgraceful, obscene and unlawful.

"For children to suffer this outrage, when they are unable to attend school in person and when distance learning is so critical to our young people, is shameful.

"Our advice would be to ask parents, pupils and teachers never to share classroom log-ins especially on social media even with your friends or family and ensure password protection and possibly waiting rooms are added to all virtual class meetings.

"As the host, you should also be able to control who is included in the virtual class and remove anyone who shouldn't be there immediately.

"It is essential that if this ever happens to you or someone you know or care for you contact the Police as soon as possible."