Cigarette-style health warnings should be placed on social media apps to protect children from harm, the Liberal Democrats will say.
In a drive to make the internet safer for young people, the party also wants to introduce a “doomscrolling cap” which would prevent their social media feeds from endlessly providing new content.
Victoria Collins, the Lib Dem science and technology spokesperson, will lay out the plans in a speech at the party’s conference in Bournemouth on Monday.
“If we are going to take on this multibillion-pound industry we need to be brave,” she will tell the conference.
Ms Collins will add: “We have long recognised that where online content poses a threat to public health, we need to know. That’s why I’m calling today for addictive social media apps to come with mandatory health warnings for under-18s.
“Just like cigarettes or alcohol, these addictive products carry well-documented risks, especially for young people.
“The evidence is clear that excessive use of these apps exposes children to mental health issues, to anxiety, sleep disruption and to real harm to attention spans. Don’t they deserve to know that?”
The intervention into the field of protecting children on social media comes after party leader Sir Ed Davey continued his spat with tech boss Elon Musk.
Sir Ed has called for Ofcom to investigate Mr Musk’s X platform for allowing images of child abuse and self-harm instructions to proliferate.
The US-based businessman has been critical of Sir Keir Starmer’s Government for introducing the Online Safety Act, aimed at protecting children online, but which Mr Musk says has a chilling effect on free speech.
Sir Ed is expected to attack Mr Musk in his conference speech on Tuesday.
His party’s science spokesperson Ms Collins also turned up the heat on the Government for not going far enough to defend children from harmful online content.
She said: “Peter Kyle, until recently the science secretary, has mooted time caps or curfews on addictive social apps – but moves on to another department leaving behind a record of failure.
“The Government must finally deliver and introduce a doomscroll ban, that caps the amount of time children can spend on these addictive apps.”
Polling commissioned by the Lib Dems ahead of the tech-focused speech found 80% of parents of school-aged children have reported at least one negative behaviour in young people because of excessive phone usage.
The poll, carried out by Savanta, interviewed a representative sample of 611 UK parents of school-aged children online between August 22 and 26.