Keir Starmer is to ban under-16s from major social media apps such as TikTok, Instagram and X in sweeping restrictions described as “Australia plus”, the Guardian understands.

In a major policy shift far tougher than previously briefed, the prime minister will announce that teenagers will be banned from all the main social platforms. Online products that are not covered by the ban – such as gaming apps – will face new restrictions such as having the option to chat to strangers removed.

There will also be restrictions for older teenagers up to the age of 18 that prevent “scrolling” late at night.

Australia became the world’s first country to implement a nationwide social media ban for children under 16 in December 2025. Children are restricted from 10 major platforms – TikTok, YouTube, Instagram, Reddit, Facebook, X, Threads, Snapchat, Twitch and Kick – and UK government sources indicated that its ban on major platforms would apply to a similar range of apps.

Government sources said protecting teenagers from harmful addictive content, such as through infinite scrolling, as well as from contact with strangers, were the key drivers of the hardline measures.

Under-18s will also be banned from accessing romantic or sexual AI chatbots. “There are no half measures here,” one said.

The government may need to legislate to enforce the ban and to give itself flexibility to adapt to new technology, though the Children’s Wellbeing and Schools Act does give ministers some powers already.

The government said on Sunday that nine out of 10 parents backed a minimum age of 16 for accessing the apps in responses supplied to its “growing up in the online world” consultation.

Nearly nine in 10 (88%) said fewer children would be exposed to inappropriate or harmful content. Almost two-thirds of young people who responded said restricting the high-risk features would make them safer online.

Along with a blanket ban on social media, Starmer is expected to announce restrictions on certain features for online products which could include gaming platforms and messaging apps such as WhatsApp, which may not fall under the category of social media apps.

Restricted features could include disappearing messages and location sharing. Starmer announced new restrictions on sending nude images last week.

Senior government sources said the prime minister, originally a sceptic of social media bans, had been won round by the evidence from the consultation. “I think he originally worried that you can’t put the genie back in the bottle with these things,” one said. “But the weight of the evidence is there, which is quite overwhelming.”

Matthew Sinclair, the senior UK director of the Computer and Communications Industry Association, an industry group, said: “Blanket restrictions on features will stifle access to age-appropriate experiences with proper parental controls, encouraging children to seek out riskier unregulated alternatives.”

Other tech industry sources described what appeared to be a rushed and at times contradictory process to finalise the ban, with speculation that the government was concerned about legal action over any perceived procedural irregularities.

Several, however, said it was unlikely that tech platforms were considering immediate legal action over anything that is to come out on Monday.

There remains a question mark over how the government might enforce age verification. Facial scans, personal IDs and banking information – most of which Ofcom already uses for enforcing the Online Safety Act – could be used.

If social media platforms such as Facebook and Instagram are banned for under-16s, they could be pushed to collect information on their users that some may regard as violating privacy, such as more extensive collection of government-issued IDs.

Thousands of teenagers in Australia are reported to have found ways of circumventing existing age limits on social media.

The culture secretary, Lisa Nandy, said on Sunday that restrictions on social media would not be a panacea but would protect young people better.

“It does mean that you … stop the situation where kids as young as eight, nine, 10, 11 are going on to social media sites because all of their friends are on them at an age when, frankly, they’re not really emotionally equipped to be able to cope with it.

“I don’t think banning social media on its own is the silver bullet solution, but I do think Australia has shown very clearly that it has a significant role to play.”

Some child safety campaigners, however, have said they believed a full ban would mean tech companies did not act to make content safer. The chief executive of the Molly Rose Foundation, Andy Burrows, said it was a “gamble on an unenforceable social media ban that will quickly unravel”.

He said it would “fail to tackle fundamental product safety risks issues and leaves parents with a false sense of safety. A majority of children will continue to use high risk sites that will have no incentive to implement robust protections.”