Teenagers are being exposed to graphic images on social media that promote life-threatening sexual acts, such as strangulation and erotic asphyxiation, prompting concerns that this is “normal” for a generation.

An investigation by this newspaper has uncovered hundreds of images of sexualised choking and strangulation on the virtual scrapbook Pinterest, the photo-sharing platform Instagram, which is owned by Facebook, and the microblogging site Tumblr. All three allow children as young as 13 onto their sites.

The images, which include pictures of young women being pinned down and strangled by men, and women with gags over their mouths, are often posted under hashtags such as #daddy, #chokingkink, #breathplay and #strangle.

On Pinterest there were images of children being gripped by the throat. One picture on Tumblr