It’s uncomfortable to tell youngsters about the dangers, but there are ways to get the message across sensitivelyWhen Rachel spoke to her three-year-old daughter Hannah about how to keep safe from sexual abuse, her response was devastating. “I said: ‘Where your pants cover; that area is for you. No one else can touch this area.’ I expected her to just say ‘OK’ but instead she said: ‘Ron puts his fingers up there.’

“Ron was a friend. He was someone who I trusted so much,” Rachel said. Ron Wood, 60, of Chaddesden, Derby, was jailed for eight years in February for sexually assaulting Hannah.

Since details of the late Jimmy Savile’s prolific abuse of young people have emerged, awareness of sexual abuse has risen dramatically. Allegations have been made against a succession of big names in television and radio in the 70s and 80s. Last month Stuart Hall, 84, of It’s a Knockoutfame, was sentenced to two years and six months for indecently assaulting a 13-year-old girl, a term he will start after completing 30 months given to him last year for similar offences against 13 girls, one as young as nine, between 1967 and 1986. Celebrity publicist Max Clifford, 71, is currently serving eight years after being convicted of indecently assaulting girls and young women between 1977 and 1984. Politicians have been drawn in, too: police are investigating historical allegations of sexual abuse at a school linked to the Liberal MP Cyril Smith, who died in 2010. Then there is the series of revelations about abuse in past decades of pupils at various British boarding schools, as well as the stories about the more recent grooming and sexual exploitation of young girls by gangs of men.

Abuse of minors is never out of the news for long, raising questions for millions of parents about how best to protect their children. They know these stories are the tip of the iceberg: police recorded more than 23,000 sex offences against children aged under 18 in England and Wales between April 2012 and March 2013. In fact, 5% of UK children have experienced sexual abuse (anything ranging from rape to inappropriate touching), according to the NSPCC, and 90% of these knew their abuser. Yet many feel awkward talking about the subject with their sons and daughters, unsure of the words to use and how to explain keeping safe. Some feel it is too early to talk about sex with them or worry about scaring them. But with the likes of Hall and Clifford invading the nation’s living rooms, and curious children wondering why those stars are in court, is silence any longer an option?

Aware of these problems facing parents, the NSPCC launched its “underwear rule”, which is a form of “green cross code” against sexual abuse: clear, simple and easy for even very young children to understand (20% of all recorded sexual offences against children involve under-11s). The message is “privates are private”, and if you feel uncomfortable, “speak out”. First released last July, the campaign was rebooted in March with television adverts and the backing of celebrities Abbey Clancy and Melinda Messenger. John Cameron, the NSPCC’s head of child protection, said: “Offenders will only approach children if they can be pretty certain the child will keep quiet and not speak out. Savile was an excellent example of someone using his authority and influence over children so they did not say anything. A lot of the children knew these things were wrong and were not comfortable, but didn’t know who to talk to and were afraid of speaking out.”

There is no need to talk about sex when using the underwear rule. The charity devised the acronym Pants to help remember the key points: Privates are private, Always remember your body belongs to you, No means no, Talk about secrets that upset you and Speak up, someone can help.

“We say build it into a normal conversation,” Cameron said. “You don’t have to be graphically descriptive or put the fear of God into children.”

The story of Rachel and Hannah (not their real names) and the jailing of Ron Wood is a powerful example of the rule working in practice. Rachel hadn’t thought about talking to Hannah about abuse. “She was only three years old and I didn’t think that it would be something that would happen to us.” But not long after hearing about the campaign, she said she was putting some cream on Hannah where her pants had rubbed and thought it would be a good opportunity.

When Hannah revealed that Wood had been abusing her, Rachel was stunned. She told the NSPCC: “We didn’t think something like this could ever happen to her – we hadn’t even left him completely alone with her.

“From what Hannah told us, he had used every opportunity he could when he got a few minutes alone with her to abuse her. They played hide-and-seek a lot and she told me that he always told her to hide in the bedroom and he did it then. She said he did it ‘lots and lots and lots’ of times. I was in the same house during the times that it happened, so I would never have thought that something like that could happen.”

Gillian McGhee, of Clydebank, has also used the rule with her son Aiden, five. She made it part of everyday conversation by bringing it up when she was dressing or washing him. “I did it in a drip-drip way without making it a big deal. I didn’t want to scare him and make him uncomfortable. He now talks a lot about not keeping secrets. They are wee sponges at that age and he responded really well. I used to work in children’s services and some were very damaged, from all walks of life. It doesn’t matter where you are from, this can happen to anybody. We empower the abusers by not talking about it.”

Jayneen Sanders, who has three daughters, wrote Some Secrets Should Never Be Kept after becoming angry that little was being done in schools in her native Australia to teach children self-protection from sexual interference. She believes that “forewarned is forearmed” and it’s a mistake to focus solely on “stranger danger” when children will more than likely know their abuser. She talks about body safety, saying: “It’s more palatable for parents, I want it to be part of the parenting conversation. Parents are so nervous about it and think they have to talk about sex. My book is age appropriate, sensitively done and will open up a conversation. It’s a way to put the perpetrators on watch – they’ve been hiding behind our fear of the subject. We have to stop that by talking to our children.”

Like Sanders, Dr Gordon Milson, a clinical psychologist in Manchester, is also frustrated that schools are not obliged to teach issues around body safety. He said: “I do feel that schools need to include matters of personal privacy, inappropriate touch and consent in their education curriculum. Having another source of information, such as school, and another place to discuss things if they’re worried, can only be helpful for children.”

Many parents also don’t realise that much sexual interference occurs between children – 66% of sexual abuse is perpetrated by other children and young people under 18, according to the NSPCC, and 83% of children who experience this don’t tell anyone about it. Milson said: “The high levels of abuse by peers needs to be carefully considered and within sexual education it is vital that consent and knowledge of privacy and personal boundaries are part of the information given.”

There is also a rapidly growing new threat of online abuse, particularly for girls who are being asked to perform sexual activities online, according to the NSPCC, which advises that the underwear rules apply here, too. The rise of internet pornography has an effect on peer-to-peer abuse as well. Milson said: “Children can access information via the internet, for example, which bypasses issues such as consent and gives a completely inappropriate message regarding the availability and consensual nature of intimate relationships.”

The top reasons cited by the 53% of parents surveyed in a YouGov poll last year who haven’t yet spoken to their five- to 11-year-olds are that their child is too young (43%), the need hasn’t occurred to them (27%) and they don’t know what to say (19%). It seems experts in the field of child protection have a clear message: children need to know what is private and when to speak out. Talking to children about these issues does not have to be frightening for them or awkward for the parent, but it does have to be done.