The question of how to keep children safe online is never far from parents' minds, but has come into increasing focus following the murder of 16-year-old Brianna Ghey.

Scarlett Jenkinson and Eddie Ratcliffe, who killed Brianna when they were 15, plotted the murder using messaging apps. Jenkinson had watched videos of violence and torture on the dark web.

Brianna's mother, Esther, says the government should make it harder for young people to access potentially harmful material online.

But what steps can parents take now to make their children's digital lives as safe as possible?

Children aged eight to 17 spend between two and five hours online per day, research by the communications regulator Ofcom suggests. Time spent online increases with age.

Nearly every child over 12 has a mobile phone and almost all of them watch videos on platforms such as YouTube or TikTok.

Four in five teenagers who go online say they have used AI tools such as ChatGPT or Snapchat's MyAI.

About half of children over 12 think being online is good for their mental health, according to Ofcom.

But there is a significant minority for whom that is not the case. One in eight children aged eight to 17 said someone had been nasty or hurtful to them on social media, or messaging apps.

The Children's Commissioner said half of the 13-year-olds her team surveyed reported seeing "hardcore, misogynistic" pornographic material on social media sites.

Parents concerned about what their children are seeing online can take some simple practical steps.

The most obvious is to learn about control functions, which two-thirds of parents say they use, according to Internet Matters, a safety organisation set up by some of the big UK-based internet companies.

It has a list of parental controls available and step-by-step guides on how to use them.

The way these work varies. However, those available with YouTube - the most popular platform for young people in the UK - are a good indication of the kinds of tools available.

Parents who want to reduce the likelihood of their children seeing unsuitable material can set them up with the "kids" version of YouTube, which filters out adult content.

Or, if their children are older and want to use the main site, adults can make their accounts supervised. This means they are able to review what sites they have visited.

Supervision can also be set up on Facebook messenger, via its Family Centre.

And TikTok says its family pairing tool enables parents to decide if a teenager's account is private or public.

Of course, these controls are not fool-proof.

Some adults find setting them up confusing, and some children find ways of getting round them. Ofcom data suggests about one in 20 children use workarounds.

Phone networks may block some explicit websites until a user has demonstrated they are over 18.

Some also have parental controls that can limit the websites children can visit on their phones.

Android and Apple phones and tablets have apps and systems parents can use.

These can block or limit access to specific apps, restrict explicit content, prevent purchases and monitor browsing.

Apple has Screen Time and Google has Family Link. There are similar apps available from third-party developers.

Broadband services also have parental controls to filter certain types of content.

So do games consoles - allowing parents to ensure age-appropriate gaming and control in-game purchases.

Talking to children about online safety and being interested in what they do online is also important, charities including the NSPCC say.

Making discussions about it part of daily conversation, just like a chat about their day at school, can make children comfortable with the topic.

It can also make children more likely to share any concerns they have.

The government says its new law, the Online Safety Act, will force social media firms and search engines to do more to protect users, particularly children.

It seeks to force tech firms to take more responsibility for the content on their platforms.

However, the new legislation will take some time before it is fully enforced.

And there have been recent calls for more to be done.

Esther Ghey says the Online Safety Act does not go far enough and children must be stopped from having access to social media apps.

She also wants parents to be able to download software to alert them to worrying content their children might be searching for.

However Mr Sunak has said that the Online Safety Act "protects children from harmful or inappropriate" material.