The UK is edging closer to a landmark decision on children’s online access as thousands of pupils take part in a world-first experiment testing whether restricting social media use can improve mental health outcomes. The six-week trial, led by the NHS in collaboration with Cambridge University, involves around 4,000 teenagers aged 12 to 15 in Bradford.

Participants are restricted to one hour of social media use per day, with platforms blocked entirely between 9pm and 7am. A monitoring app installed on their devices enforces the limits, preventing access to services such as TikTok, YouTube and Instagram. Researchers will compare anxiety, depression and sleep patterns among the participants with those of a control group allowed unrestricted access.

The trial comes amid growing political momentum for tougher regulation. Ministers have confirmed plans to consult on limiting social media use for under-16s following a House of Lords vote on amendments to the Children’s Wellbeing and Schools Bill. Prime Minister Sir Keir Starmer, who previously opposed a ban, announced a six-month consultation after pressure from more than 60 Labour MPs advocating an Australia-style approach. Australia last month enacted legislation barring young teenagers from social media platforms.

Senior figures across party lines have echoed the call. Former schools minister Lord Nash urged immediate action, warning of a looming “societal catastrophe” if delays continue. Technology Secretary Liz Kendall pledged a rapid consultation, with conclusions expected by summer, exploring options including a ban, raising the digital age of consent and restricting companies’ use of children’s data. Conservative figures, including Kemi Badenoch, have also signalled support for a ban if elected.

Public backing has intensified the debate. A letter signed by actor Hugh Grant, Sophie Winkleman and Esther Ghey — whose daughter Brianna was murdered in 2023 — urged party leaders to support a full ban. Citing polling by Parentkind, the letter said 93 per cent of parents believe social media harms children and described the proposal as the most decisive route to safeguarding young people online.

However, opposition has emerged from children’s charities including the NSPCC, Childnet and the Molly Rose Foundation. In a joint statement, 42 organisations warned that a blanket ban could create a false sense of security, pushing children into less regulated online spaces rather than addressing underlying risks such as abuse and harmful content.

Researchers behind the Bradford trial stress that the study is independent of government policy. Professor Amy Orben, the project’s co-lead, said while evidence of severe online harms is “irrefutable,” the broader impact of time spent on social media remains poorly understood. Co-lead Dr Dan Lewer added that teenagers themselves recognise risks including sleep disruption, online bullying and the erosion of real-world relationships. Data from the Born in Bradford study shows young teens average around three hours of daily screen time, with heavier use linked to poorer mental health.

As the consultation unfolds, ministers are also considering alternative measures such as night-time curfews, app time limits and restrictions on addictive design features like infinite scrolling. Guidance for parents on appropriate screen time for children aged five to 16 is expected later this year, setting the stage for one of the most consequential digital policy decisions the UK has faced.