Headteachers are warning parents that online 'suicide game' Momo is being spliced into videos of Peppa Pig and Fortnite on YouTube.

Schools across Britain say children are being targeted by creepy images and clips of the disturbing character on the video sharing website.

The Momo challenge - which has been linked to two children's deaths - encourages youngsters to harm themselves and in some cases even take their own lives.

Today schools began issuing warnings on their websites and social media accounts saying they have been contacted by hundreds of concerned parents.

Schools across Britain say children are being targeted by creepy images and clips of the disturbing character (pictured) on the video sharing website

They said that the clips appear in the middle of seemingly innocent videos of children's cartoon Peppa Pig, or computer game Fortnite.

Haslingden Primary School, Rossendale, near Blackburn said in statement: 'We have become increasingly aware of highly inappropriate videos circulating online and are being viewed by children across the school.

'These video clips are appearing on many social media sites and YouTube (including Kids YouTube).

'One of the videos starts innocently, like the start of a Peppa Pig episode for example, but quickly turn into an altered version with violence and offensive language.

A number of schools have been warning parents to be vigilant in posts on their social media sites

'Another video clip is going by the name of 'MoMo' which shows a warped white mask which is promoting children to do dangerous tasks without telling their parents.

'As you can imagine, this is highly distressing for the children to view. We encourage you to be vigilant when your child is using any device or watching any clips.'

Other warnings were issued by Newbridge Junior School in Portsmouth and Offley Endowed‏ Primary school, near Luton, Bedfordshire, which said this morning: 'We are aware of Momo challenges that are appearing as pop ups on Youtube kids, Fortnite & Peppa Pig etc & will be talking to the children about it in Assembly.

Parents have been told the creepy images and clips appear in the middle of YouTube videos of Peppa Pig (pictured) and Fortnite

'Please be vigilant with your child using IT. We are asking children to tell a grown up & not click on Momo images.'

Northolt Community Special School in Hull, East Yorkshire said: 'We are aware that some nasty challenges (Momo challenge) are hacking into children's programmes.

'Challenges appear midway through Kids YouTube, Fortnight, Peppa pig to avoid detection by adults.

'Please be vigilant with your child using IT, images are very disturbing.'

Craig Wardle, headteacher of Cleve House school in Bristol, sent a letter to parents warning them about the online craze.

Videos of computer game Forntite, hugely popular among children, are also being targeted by the Momo challenge

It said: 'Light-hearted and fun at the outset, this game experience quickly darkens, absorbing players who are encouraged to perform acts of violence and self-harm through a series of progressively risky tasks. It is rapidly spreading across the world.

'The challenges issued in this game present a serious risk to the safety, welfare and well being of young people in our school and in the UK.'

Mr Wardle, 51, said each class has been spoken to by teachers about how to stay safe online.

Speaking today he said: 'It is something that came out of the blue. The first time we came across it was when a concerned parents got in touch.

'It was on the radar of some key stage two children so it's fortunate a parent raised it to us.

The letter recieved by parents of pupils at Cleve House School in Bristol warning about the online suicide game Momo

'We have discussed it with each class. We talked to them about what to be cautious about online. Things don't always turn out to be what they appear as.

'It is a danger and it would be irresponsible for us to disregard it.

'There are enough dangers out there as it is and we have got to be aware of any new ones that come along.'

Momo features a creepy woman with dark hair, a devilish grin and protruding eyes, who entices children through a WhatsApp account and then sends them images and instruction on how to harm themselves and others.

Momo threatens that if the children don't do what she says then she will 'curse them'.

This week a concerned mother from Manchester, who asked to remain anonymous, said she was 'deeply alarmed' when her seven-year-old son's teacher told her he had been making threats to other pupils at school.

After discussing it with her son, she discovered he had been influenced by the Momo challenge and in a post to the Love Westhoughton Facebook group she revealed the horrendous things that Momo had told him to do.

She said: 'When I collected him from school the teacher asked to talk to me.

What is the Momo 'suicide game' and where did it originate? The Momo challenge was first reported in July last year, and was described as a new 'Blue Whale' style suicide game. It started on WhatsApp, and challenged users to contact 'Momo' by sending messages to an unknown number. The user was then hounded with frightening images and violent messages. Children are contacted on WhatsApp and other online platforms by the cartoon Momo, who is encouraging children to self-harm No one knows exactly where Momo originated, or who is behind the disturbing trend, though it was linked to at least seven phone numbers beginning with codes from Japan and multiple countries across Latin America. The Momo challenge then started popping up in videos that were posted to social media. The Momo avatar was created by Japanese special effects company Link Factory and designed by Midori Hayashi who has no relation whatsoever to the game. The scary design originally featured at Tokyo's horror art Vanilla Gallery under the name Mother Bird. Momo's features include a painfully gaunt face, bulging eyes and an unnaturally thin and long smile. In September a 12-year-old girl and 16-year-old boy in Colombia are said to have killed themselves after playing the a suicide challenge game on WhatsApp. The tragic deaths happened within the space of just 48 hours in the municipality of Barbosa, in the north west Colombian area of Santander. Local media report that the body of the 16-year-old boy was found first and that it is believed he knew the 12-year-old girl. He reportedly passed the game Momo game onto her before his death. Within 48 hours, she too was found dead. It is reported she was found hanged. The two youngsters who died had their phones seized by police, who say they found messages linked with the game. Advertisement

'She said he had made three kids cry by telling them that 'Momo was going to go into their room at night and kill them'.

'When we got home I spoke to him about this and he told me that some kids at school had told him to look at the 'Momo challenge' which he did.'

She added: 'When we watched a video the 'Momo' character told him to tell everyone to fear Momo or it will kill him in his sleep. So I have one very frightened little boy and some deep concerns about the kids in his school.

'Parent controls are as tight as could be and this **** still slips through. So if you have a child it would be well worth it to open up a dialogue about idiots online and try to get ahead of this.'

Yesterday mother Lyn Dixon told how her eight year old son became frightened of the dark and was scared to be alone after Momo appeared on YouTube videos he was watching.

The mother, from Edinburgh, said: 'He showed me an image of the face on my phone.

'He said that she had told him to go into the kitchen drawer and take out a knife and put it into his neck.

'We've told him it's a load of rubbish and there are bad people out there who do bad things but it's frightening, really frightening.'

Ms Dixon added: 'It started with him not wanting to go upstairs on his own because it was dark up there.

'He was terrified and wouldn't sleep in his own bed and then we got to the bottom of it and we explained it wasn't real.'

Police have also issued warnings about the challenge.

Officers in Northern Ireland are now working with forces across the UK in order to stop the game.

Other forces including the Met Police in London have sent out information via borough team facebook pages from the National Online Safety campaign about Momo.

Detective Sergeant Elaine McCormill from the Police Service of Northern Ireland, said: 'This extremely disturbing challenge conceals itself within other harmless-looking games or videos played by children and when downloaded, it asks the user to communicate with 'Momo' via popular messaging applications such as WhatsApp.

'It is at this point that children are threatened that they will be cursed or their family will be hurt if they do not self-harm.'

Derbyshire police are also urging parents to visit an article on the website parentzone.org.uk.

The article says: 'Many prominent YouTubers create videos of themselves trying to reach out to Momo which get many views through, for example, sharing on social media.

'Make sure that they know that they should not be trying to contact strangers via social media platforms and instant messaging apps. It could be useful to show them how to enable privacy settings and disable location sharing so that they don't fall victims to scams.'

National Safety Online provides courses and educational resources to support UK schools to educate the whole school community, including parents, in Online Safety.

They tweeted on Tuesday: 'Today we've heard from hundreds of concerned schools and parents about the horrifying £Momo challenge which has reportedly been appearing in children's YouTube videos, causing panic and upset amongst young people. We hope you find our guide useful.'

An information page can be downloaded from their website.

Advice includes, telling children Momo is not real, be present when your child is online, check device settings and parental controls and report and block anything untoward you see.

YouTube today insisted that the content had not been found on YouTube Kids, and said said it permitted news stories and videos that are intended to raise awareness of and educate against the challenge.

It also said it had not had any links flagged or shared with it that violated our guidelines by showing or promoting the Momo challenge.

A spokesman for YouTube said: 'Contrary to press reports, we have not received any links to videos showing or promoting the Momo challenge on YouTube.

'Content of this kind would be in violation of our policies and removed immediately.'