"Many parents are out of touch with the dangers faced by their children on tablets and smartphones, according to a poll by BBC Learning.
Almost one in five children said they had seen something on their devices that had upset them, twice the number parents had thought.
A separate study found that just over 20% of parents do not monitor what their children are doing online.
The research was commissioned as part of Safer Internet Day.
While 90% of the parents surveyed by the BBC in England said they had spoken to their children about staying safe online when using a tablet or a smartphone, most said they allowed their children to use them unsupervised."
http://www.bbc.com/news/technology-26121434