How often do children encounter hate speech online?

One in three internet users between the ages of 12 and 15 say they saw "hate speech" online in the past year, according to Ofcom's latest survey of children's media habits.

It is the first time the UK regulator has posed a question about the topic in its annual study.

"Obviously this is a real concern and like any parent I'd be worried about [hate speech] too," Emily Keaney, Ofcom's head of children's research told the BBC.

"But we also know that children are likely to tell an adult about it - probably a parent or teacher - and that parents are mostly talking to their children about how to stay safe online."

The study indicates parents are becoming more proactive about their children's online safety.

More families said they used home network-level filters to block offensive content than last year. Likewise, more parents said they had changed the settings on their children's devices to prevent them downloading apps when unsupervised.

But one child safety expert said such technical fixes could only go so far.

"We are getting better at filtering out inappropriate content [such as pornography] but speech is considerably more difficult to deal with," said Stephen Balkam founder of the Family Online Safety Institute.

"Parents must talk with their kids and convey their offline real-world values because ultimately it has to come down to the kids' own sense of what is right and wrong.

"One of the things we are trying to encourage is that kids should act on this stuff in a way that empowers them. That can involve telling a site like Facebook or YouTube that they have seen harmful stuff and then witnessing it be removed."

For more information, visit the BBC Website