Children who view clips of Sesame Street and Peppa Pig on YouTube are on average just three clicks away from explicit adult material on the site, including nudity and violence, according to research.

A study released to mark Safer Internet Day on Tuesday found that graphic footage was available to children who had viewed clips of popular kids' TV programmes.

In one example, YouTube users were two clicks away from footage of a woman giving birth after viewing a Sesame Street video, said the security company Kaspersky, which carried out the research. The list of recommended videos, displayed on the right-hand side of the page after a video has shown, provided a path to the explicit material, the researchers found.

A separate study of 24,000 young people found that 27% of seven- to 11-year-olds and nearly half of 11- to 19-year-olds had come across something they thought was "hurtful or unpleasant" online in the past 12 months.

The research will underline growing concerns about the lack of robust protection for children in cyberspace.

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.

"We have already taken great strides to make internet access more family friendly and we will continue to work with the industry, parents and young people to build an even safer internet in the future."

The Kaspersky study on YouTube gave various examples of where children could be between two and four clicks away from objectionable material on the world's most popular video site. In one example, a music video featuring swearing and guns was two clicks away from a Rastamouse clip thanks to YouTube's "suggested videos" feature.

"It's worrying to see just how simple it is for children to access videos of an adult nature on YouTube," said David Emm, a senior security researcher at Kaspersky Lab.

YouTube has a safety mode that can block inappropriate material, such as pornographic material and objectional comments. Google admits that the safety feature cannot be "100% accurate" because it relies in part on users to flag inappropriate videos for the safety mode to work.

Like Facebook, YouTube recommends that it is only used by viewers aged 13 and over. However, both companies concede that this cannot be fully policed.

The survey of 24,000 young people, conducted by the UK Safer Internet Centre, found that more than a third of seven-year-olds and 45% of 16- to 19-year-olds said they had not been taught about staying safe online.

Kaspersky's Emm said the research on YouTube 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," he said.

A spokeswoman for YouTube said: "We take safety on the platform very seriously and work closely with organisations such as charities, others in our industry and government bodies dedicated to protecting young people.

"YouTube has a variety of parent and educator resources on the site such as the online curriculum, as well as tools such as safety mode which parents can turn on to filter out potentially objectionable content and comments."

Some internet providers offer parents the ability to filter out inappropriate material, such as pornographic or violent videos, as default. BT, the largest internet provider in the UK, has family protection controls that can filter YouTube content and block unsuitable websites. TalkTalk's HomeSafe package has been activated by 460,000 of its 5 million customers. © Guardian News and Media 2013