Children face restrictions on smartphone use to prevent them doom scrolling for hours on social media.
New legislation backed by a cross-party group of MPs aims to restrict the ability of under-16s to access addictive social media content on sites like Tik Tok and Snapchat.
The Safer Phones Bill, which will be published on Tuesday would raise the age of internet adulthood from 13 to 16, preventing younger children from accessing standard social media sites without parental consent.
It would also impose a mandatory ban on mobiles in schools, requiring heads to prevent children having access during the school day.
Childrens Commissioner Dame Rachel de Souza (pictured) backs new legislation to restrict the ability of under-16s to access addictive social media content on sites like Tik Tok and Snapchat
The Safer Phones Bill, which will be published on Tuesday would raise the age of internet adulthood from 13 to 16, preventing younger children from accessing standard social media sites without parental consent
And Ofcom would be given new powers to enforce a code of conduct aimed at preventing children gaining access to sites that are addictive by design.
Labour MP Josh MacAlister, who is bringing forward the proposals as a private members bill, said the measures would act as a digital seatbelt to protect youngsters online, and give reassurance to parents worried about their childrens phone use.
Mr MacAlister, a former teacher who led a review of childrens social services for the last government, said: The evidence is mounting that children doom scrolling for hours a day is causing widespread harm.
We need the equivalent of the seatbelt legislation for social media use for children.
Adults find it hard enough to manage screen time, so why are we expecting children to manage this addictive content without some shared rules?
Parents are in an impossible bind over whether to ostracise their child from social media or expose them to the harms and addiction of content.
Countries around the world are now taking bold action and our children risk being left behind. Its time to have the national debate here in the UK.
Ministers are said to be interested in the proposals, which will require government support to become law.
Dame Rachel de Souza said: Children tell me that they want to enjoy the benefits of the online world and to be protected from harmful content and harmful behaviours. This Bill will secure the proactive approach to keeping children safe online that is required in an era of evolving technology.
Science and technology secretary Peter Kyle said earlier this month he was open minded about the steps needed to give children greater protection online.
Former Tory education secretary Kit Malthouse, who is backing the Bill, said: The growing evidence of the impact of smartphones on kids is deeply alarming.
So being clear about our expectations from providers and regulators, and their duties towards our children has to be a step in the right direction.
Childrens Commissioner Dame Rachel de Souza also backed the proposals, which she said would strengthen the Online Safety Act and ensure that tech companies consistently put childrens safety ahead of their profit margins.
She added: Children tell me that they want to enjoy the benefits of the online world and to be protected from harmful content and harmful behaviours.
This Bill will secure the proactive approach to keeping children safe online that is required in an era of evolving technology.
The legislation stops short of imposing a total ban on smartphone use, which is being pushed for by some campaigners.
Instead it would raise the age at which children can give consent for their data to be used by social media firms from 13 to 16. Supporters of the bill believe that without access to data, tech firms will find it much harder to target addictive and harmful content at youngsters.
But it would also commit ministers to reviewing the success of the measures - and leave open the idea of limiting under-16s to so-called dumb phones incapable of running social media apps in the future.
It comes after internal documents from TikTok claimed that the social media site, which is hugely popular with teenagers, can hook new users in less than 35 minutes.
A TikTok spokesman told The Times: We have robust safeguards, which include proactively removing suspected underage users, and we have voluntarily launched safety features such as default screentime limits, family pairing and privacy by default for minors under 16.