Pop stars appearing in highly sexualised videos are a bigger danger to children who use the internet than hard core porn, a child protection expert has told a House of Commons select committee.

Jim Gamble, the former head of the government’s Child Exploitation and Online Protection Centre and current chair of the safeguarding children board in Hackney, East London said that popstars like Miley Cyrus had a “far greater” impact on young people, The Daily Telegraph reports.

Speaking to the Culture, Media and Sport select committee, Mr Gamble said there was no filter for pop videos, unlike for internet pornography,  

He remarked: “I think there is far too great a focus and emphasis on [the online pornography] side of the debate, if you look at Miley Cyrus, if you look at some of the other pop stars and their behaviour, that has a far greater and much more easily accessible influence on young people today than actually seeing adult, or hardcore pornography, for that matter.

“There is no debate or discussion really about that because you have young pop stars who young people want to emulate behaving in a highly sexualised way – and there is no filter [for that.]”

Cyrus was criticised in August following a provocative performance at the MTV video awards.  

Her transformation from a Disney Channel actress was completed by the release of her new music video Wrecking Ball in which she is mostly nude.

Mr Gamble also told the committee that parents had make the decision about what inappropriate content children should or should not watch unless it was illegal.

He added that it was “absolutely right” for internet service providers to ask parents to make an “active choice” about whether or not they wanted over-18 content in their homes.

He said: “If parents are prompted to make a decision then I don’t think you can do more than that – you aren’t going into their homes and look after their children for them.

“The reason it is inappropriate and not illegal is because it is not against the law and thereby quite appropriate for a parents or a carer or person who has a duty of care to make that decision.”

Meanwhile, a BBC News feature has revealed that children as young as four are being shown cartoon pictures of adults watching pornography during sex education classes.

Sex education consultant Lynnette Smith runs sessions for primary schools, in which children give a thumbs up or down to different cartoon scenarios, such as grabbing a woman’s breasts or pulling at a boy’s underwear.

The students are also asked when is acceptable to “have a little rummage in your underwear”, and the answer given is “somewhere private like the bathroom”.

But one teaching union has warned that such sessions may not be suitable for all primary schools because “Innocence is precious”.

Lynnette Smith runs the same presentation for children between the ages of four and eleven.

A BBC reporter sat in on a session for seven to nine-year-olds run by Lynnette Smith at a primary school in North Lincolnshire.

Children were heard giving ‘cries of disgust’ and laughing during the half-hour presentation, which also involved the students naming body parts from a picture of a naked girl.

Parents at the school were said to be horrified when first informed that the presentation would take place.

One mother said: “I thought, no they’re only seven.”

During the session, other scenarios given the ‘thumbs down’ included looking under toilet doors when someone is inside and showing your bottom to a camera.

Russell Hobby, the general secretary of the National Association of Head Teachers cautioned that: “You don’t want to start too young”.

He said conversations about online dangers in primary schools should be “general warnings that they may see things they don’t like online and advice on what to do about it when they do”.

But Lynette Smith has defended her programme, saying: “My bottom line is to ask, ‘From what age are they vulnerable?’”

Sex and relationships education is not compulsory in primary schools, despite pressure from various campaign groups.

David Cameron said in September this year that children can be warned about the dangers of online pornography without an overhaul of sex education.