Children who watch Peppa Pig or Sesame Street on YouTube are an average of just three clicks away from explicit adult material on the site, according to new research.
Clips showing graphic footage such as nudity or violence were found in the recommended videos list displayed after popular kids’ TV programmes had been viewed.
Meanwhile campaigners have urged that children as young as five should be given lessons in how to use the internet safely.
David Emm, of Kaspersky Lab, which conducted the YouTube research, said: “It’s worrying to see just how simple it is for children to access videos of an adult nature on YouTube”.
He said the research on YouTube, released to mark Safer Internet Day, highlights the potential danger of leaving children unattended when using the internet.
“The ease of access to inappropriate content online is part of the wider debate about whether the internet should be controlled or censored,” said Mr Emm.
The children’s minister, Edward Timpson, said: “We know how important it is that young people are safe and supported while using the internet, and that parents are confident their children are protected from accessing harmful content.”
Claire Lilley of the NSPCC warned: “We are facing an e-safety time bomb”, and commented that online abuse was one of the biggest issues facing young people today.
ChildLine, which is visiting UK primary schools to teach about internet safety, said its helpline took some 3,745 calls about abuse via the internet and mobile phones last year, with most callers aged between 12 and 15.
Some 250 callers said they were being groomed for sex online. There was also a 70 per cent increase in calls about online pornography with 641 calls, some from children as young as 11 years old.