For many parents the world of cyberbullying is unchartered territory – something they’ve never dealt with firsthand and may find difficult to address with their child.

To mark Stand Up To Bullying Day on Wednesday 21 June, The Diana Award, a charity set up in the memory of Diana, is calling for “cyber lessons” in digital resilience to be introduced in schools.

But in the meantime, an increasing number of parents are struggling to find out whether their child is being cyber bullied – as research from a ChannelMum survey found that 17% of school children are now bullied online.

So what can parents do?

Cathy Ranson, Editor of ChannelMum said: “Cyberbullying can be one of the toughest types of bullying to cope with. Smartphones and other devices mean there is no escape and it can happen around the clock.

“And the internet never forgets so the words and images are preserved online for others to see – meaning bullying can spread.”

The NSPCC told HuffPost UK, that there is “no one sign” that indicates a child is being bullied online, but there are lots of things that parents can be on the look out for, if their children are not giving anything away.

1. They are being secretive with their devices.

Although no child wants their parents looking at their messages (you probably wouldn’t want them reading yours either), and they are entitled to privacy, if your child becomes more protective of their device suddenly, then this is a red flag.

Be aware this behaviour won’t necessarily manifest as hiding the device (fewer than 3% of kids do this, according to Channel Mum), but if your child is generally being secretive about what they are doing online, appearing anxious or upset after using their mobile phone, or stopping abruptly and putting the device down, you might want to check in.

2. They are constantly checking their device.

We all know that our children can be addicted to their devices, but if they seem unwilling to part from it (won’t leave it alone at the dinner table or put in your bag when you are out), then you might want to ask if everything is okay.

Lauren Seager-Smith, CEO of anti-bullying charity Kidscape, said: “Checking their device isn’t unusual, but if your child seems unusually anxious and obsessive it can be a sign they’re being targeted.”

3. They are reluctant to switch off at night.

Being physically joined to their device will not just be a problem during the daytime, but in the evenings when their peers (and the potentially bully) are most likely to be online, so their anxiety might be heightened later at night, or around bedtime.