Bereaved families and MPs are urging the government to take tougher steps to protect younger teenagers from "horrific" content on social media.
The Australian government's decision to legislate for a smartphone ban for under 16s has reignited the debate in the UK about further restrictions, and a Labour MP is hoping to get government support for curbs on social media.
Stuart Stephens is among those campaigning for the government to go further and spoke to Sky News.
His son Olly was just 13 when he was murdered by other teenagers following a row which began on social media.
Mr Stephens said his son had been trying to stand up for another child who was a victim of "patterning" - humiliating someone and circulating it on video to blackmail them. Three 14-year-olds were jailed for Olly's murder in 2021 - following an investigation involving 11 social media platforms.
"We are angry," Mr Stephens said. "Without a doubt, without all that interaction he would still be here.
"There's no accountability. These platforms are put out; kids use them, people get hurt, and we need to shine a light on that.
"I firmly believe that I lost my son because of weak governance and poor legislation, full stop, which is why we are doing what we are doing.
"I can't show you any of the stuff that we saw on his phone, but it's horrific. And a lot of that stuff you can't unsee. And especially as a child, you've got a developing brain and you bombard them with horrific stuff that's going to change them as an adult, and that's not beneficial for society."
Mr Stephens added: "You think this is never going to happen to you.
"He went into his world with the mobile phone. We need to bolster the legislation that's already there, not weaken it."
Mr Stephens supports a private members' bill being drafted by Labour MP Josh MacAlister which would raise the age of internet "adulthood" in which a child can give data to social media apps from 13 to 16 - in order to stop them being bombarded with unsolicited content via algorithms.
This would go further than the measures in the Online Safety Act, passed a year ago, which the regulator Ofcom will be implementing in phases from next year.
Ministers have promised sanctions for tech companies who fail to clamp down on harmful material, such as violence, explicit material and disinformation, and do not implement rigorous age verification for their platforms.
The Technology Secretary, Peter Kyle, is not minded to enact a full smartphone ban for under-16s but has said that nothing is "off the table".
Mr MacAlister, a former teacher and now MP for Whitehaven and Workington, believes parents need to be empowered to stop their children "doom-scrolling" on social media and is hoping to get government support.
The MP, who has held meetings with parents, health professionals and tech experts, told Sky News he was concerned by figures showing the average 12-year-old is spending 21 hours a week online.
"We've reached a point where this is a topic of discussion at almost every family dinner table in the country. Parents, teachers, children themselves recognise the scale of this problem," Mr McAllister said.
"We've got the Online Safety Act here in the UK, which is a great landmark initial piece of legislation, focused on obviously harmful content - violent images, pornography, those sorts of things.
"But in places like Australia, states in the US and France, governments are saying actually there is a wider effect of addictive social media smartphones and that's taking children away from other activities.
"My bill is about trying to put that debate here into parliament and to persuade the government to act, to do really one simple thing through a number of measures.
"That is to make the version of smartphones that children use under 16 different to those above 16 - safer, less addictive; kick children off of them after they've spent a fair bit of time on their mobile.
"I don't think that this is an issue where the genie is out of the bottle. We can absolutely set some new rules around this."
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Sky News spoke to parents who feel that even legal content is taking over their children's lives. The group Smartphone Free Childhood, set up by parents, now has 150,000 members promoting the use of "brick" mobile phones without apps.
One of its members, Susie Husemeyer, is trying to restrict smartphone use for her daughter Amelia, who is 12 years old.
After giving her a smartphone in her last year of primary school and trying to impose a time limit, she had second thoughts and has now disabled the internet on the device.
Amelia said: "I have messages, music to listen to on the bus, and calls. There's a lot of peer pressure that's like, how come you don't have WhatsApp? I get a lot of my friends saying, 'Your parents are so boring. How come your parents don't let you do this?'"
But while her friends are often glued to their phones, she supports her parents' decision.
"It's not good for your mental health, especially without any restrictions.
"Sometimes I think I wish I had WhatsApp, as people will have a birthday party and set up a group chat about it and I'll be completely left out.
"But usually I don't. It would be easier if everyone was banned."
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Susie said: "There is no doubt about it, she is left out. I think that parents like me are just in such a hard place because we're trying to do the right thing by our children.
"But at the same time, our children's peers are all using phones that have all these things enabled. And these devices are just so addictive.
"My message to government would be we are in desperate need of preserving our children's childhoods because childhood lasts a lifetime, a good childhood lasts a lifetime, and a distracted childhood lasts a lifetime too, in terms of how the brain develops."
Some children's charities say a total ban on smartphones or social media punishes teenagers and ignores the benefits of phones when used safely.
Sir Peter Wanless, the NSPCC's chief executive, said: "Social media is now an integral part of young people's lives. It provides them with opportunities to communicate with friends and family, to learn and be creative.
"We understand the concerns about children having access to social media that is fundamentally unsafe for them. However, children deserve to have age-appropriate experiences online rather than being cut off from it all together."
(c) Sky News 2024: Bereaved families and MPs call for tougher measures on mobile phones for under-16s