An app for teenagers to share fun videos has become a kind of "hunting" for pedophiles that schools have issued warnings directly to parents.
TikTok – one of the most downloaded apps from the world – reveals children as young as five to give birth pests, cruel taunts and anorexia glory and self-harm.
One head of school even warned: "There was doubt that the app was used for teenage girls."
The app is a great success with people under 16, and heads of dozens of schools – including early years – have sent letters to thousands of parents across the UK.
TikTok says that consumers must be at least 13 years old – but they do not ask for any proof.
Recently, it has added the ability to live-stream, making it even more threatened.
That reveals young people to strangers' tips in real time, with only seconds to determine a response that poses risks that lead to abuse and exploitation.
Our reporting team spent this week investigating the app, that children had been using half-term.
One teenage teenage video showed while other users encouraged them: "Turn off your clothes."
Another innocent video included a woman of 15 series of raw comments from men about sex acts.
Others show teenagers are abducted mentally and users who dig up eating disorders.
One incredible teenage clip showed a skeletal ribbons. He has tagged his "#thinspo" post, for "thin inspiration" – used to seek approval for body image issues.
Our findings come in the growing demand for regulating tighter social media.
The property that belongs to a Chinese, worth up to £ 55 billion, claims to be "raw, real, and without boundaries".
But its dark side is about teachers across the country.
One Cornwall primary school said: "Parents of children in Year 3 to Year 6 have been scared by what children are exposed to."
Parents in Hounslow, London have been notified to the #htradefortrade hashtag, a sign of wanting to trade illegal content.
As well as comments on streamlining and the public, TikTok allows users to send direct messages.
One North Yorkshire school said: "If the profile is open, strangers can comment on your child's videos.
"Although this is not always a sinister, it allows predators to contact their child."
In Stockport, Manchester City, parents were informed of the #takeitoff challenge, where young women are being urged to video their own removal and school shirts.
The school told parents: "There was some doubt that the app was used for teenage girls and teenagers."
Chris Keates, from NASUWT teaching union, said: "Today is TikTok, tomorrow it will be another site.
"Young people will be at risk until those developing the sites, and their governments regulate, make security and well-being a leading priority."
TikTok – who used to run in the UK as a musical.ly – is one of the top 10 apps globally, assaulting Netflix and Snapchat.
In September, the US police arrested in New Jersey claimed that children were getting married on the app.
The NSPCC found that one in 20 children on live streaming sites had asked a strip stranger.
They said: "We know that a significant number of children are contacting them through live apps such as TikTok, misusers use them as hunting grounds. There is a scary of social networks. made over cover. "
Barnardo's Charity reported that her children's sexual exploitation team had helped victims as young as eight to younger than anyone who had seen before.
The Media, Culture and Sport Department said: "We expect technical companies to eliminate the inclusion of sexual abuse of children, give them the best to rotate online, and have a robust age check."
TikTok is an age rating on app stores so parents can give it the best to add it.
TikTok spokesman said: "We have a number of defensive measures in place and we are committed to improvement. We delete content and terminate accounts that break our guides."