If you are worried about anything you or your child come across online, you should report it immediately to the relevant organisation and to the site where you or your child saw it.
Please follow the link below from Digital Parenting which provides some practical advise for parents about keeping your children safe online;-
https://parentzone.org.uk/digital-parenting-online-safety-magazine
Below are a list of useful links to websites that will provide you with useful information about how your child can use their digital devices safely.
http://www.saferinternet.org.uk/news/staying-safe-online-this-summer
http://www.childnet.com/resources/supporting-young-people-online
http://www.childnet.com/parents-and-carers
http://www.childnet.com/parents-and-carers/hot-topics
http://www.ceop.police.uk/safety-centre/