The Momo 'suicide challenge' which has been sweeping the globe is an indisputable hoax, according to a Norfolk cyber security expert.

Concerns about the 'game', which had challenged young people to harm themselves and others, caused schools in the region including in Norwich, Fakenham and Lowestoft to issue warnings to parents and carers.

But those who were sceptical about the challenge have been proved right: according to Paul Maskall, former cyber security adviser for Norfolk and Suffolk police and now owner of cyber security consultancy Jungo, it doesn't actually exist.

Echoing charities including the Samaritans and NSPCC, Mr Maskall said the frenzy whipped up around Momo was based on little more than rumours spreading through social media and interest from the media.

He compared it to Blue Whale, a internet 'game' challenging teenagers to do increasingly dangerous things which went viral in 2016 and was later discovered to have been fake, and 'chain letters', which were sent via email and threatened grim consequences to users who didn't forward them on to friends.

'It is a viral ghost story, a complete hoax based on a Photoshopped image that has been taken out of context and which the media has said is incentivising self-harm in children,' he said.

'Because emotion is more viral than anything else parents have got worried about their children being exposed to these images.

'The biggest problem is the aftermath, like in Blue Whale, where you have people getting on the bandwagon then the hysteria creates the problem as children will seek out stuff they are not supposed to.

'It is a malicious hoax, but the internet and social media being as they are will of course perpetuate it. When you read something on social media, you are projecting your own fears onto it.

'It is the fear factor of children being exposed to things online that causes the problem.'

Following increasing news coverage of the Momo challenge in recent days, the UK Safer Internet Centre claimed it was 'fake news' while YouTube – where videos, including some aimed at young children, were said to have been spliced with graphic images relating to Momo – said it had no evidence of videos showing or promoting the challenge on its site.