Petition Tumblr porn and self harm triggering

Tumblr has porn readily available for all ages to view.Any child who has access to a computer and the internet can access not only graphic porn but ''triggers' as they call them to self harm, including how to self harm and suicide. I know this because my daughter has had access to this for years without my knowing and is now self harming and been taught how including tips on how to get tools via tumblr. I have just been on a site where there is XXX rated porn on a 16 yr old's web site. This has got to stop. All parents of teens who have internet access in their bedrooms need to be aware of what they can access. Therefore I petition the UK government to put pressure on such sites as tumblr to accept responsibility for what they allow to be published and posted for the sake of childrens mental and physical welfare and made to stop.