A mother who found her 13-year-old daughter discussing the best way to make a sex tape after reading an e-book has called on publishers to give books adult ratings to protect children.

West Hampstead mother Melissa Crighton, 45, caught her daughter and a friend reading aloud from It’s All About The Sex Face: A Guide To Becoming A Celebrity, which gives tips on how to produce a sex video to achieve instant fame.

The e-book, which costs £1.02 to download from Amazon, claims you can “actually become famous without even having a talent”.

National children’s charity the NSPCC has urged all parents to monitor their children’s e-book reading following the incident and said all book retailers, on or offline, have a responsibility to prevent children from purchasing adult material.

Ms Crighton, of Cleve Road, West Hampstead, said: “They were reading out the steps in the book about how to make a sex tape – how to produce it, how to get a co-star and how to leak it.

“I interrupted them and took the Kindle away and I spoke to them and said ‘This is not a book you should be reading.’

“I found the subject matter inappropriate. They have gone online to find books about how to get famous so it’s worrying if this kind of stuff is being sold.”

The e-book had been downloaded by her daughter’s friend on her mother’s Kindle. Ms Crighton said she informed her and the book was deleted.

The mum-of-two, a web designer, said: “I think for kids a novel on a Kindle seems more like an app, something you can quickly download. It’s more accessible than going into a shop, so it’s more difficult to monitor what children are reading.”

She added: “The Government should do something where they get publishers to say what is in the book or give them a rating.”

Guidance and “gentle age ratings” are included on some children’s books for parents but publishers are not under any obligations to do so for adult literature.

But with the arrival of e-books there are fears more children can instantly access adult literature at the click of a button.

Jon Brown, head of sexual abuse at the NSPCC, said: “It is really important to talk to your children about the risks that are out there either online or offline, in an age-appropriate way and without frightening them.

“Speak to them specifically about the risks of making a ‘sex tape’ and if it did get into the wrong hands, it could go viral online.

“We’d also urge you to be interested in what your children are reading and researching online and find out what your children’s schools are doing about these issues as part of the curriculum.

“Book retailers on or offline have a responsibility not to sell over 18 material to children and young people under 18.”