High Court refuses permission in challenge to puberty blocker clinical trial

The High Court today refused permission in judicial review proceedings challenging the authorisation of a clinical trial into the use of puberty suppressing hormones in children with gender incongruence. Judgment followed a two-day oral permission hearing heard on 27 and 28 July 2026 before Mr Justice Chamberlain.

The Claimants sought to challenge the decisions of regulatory bodies the MHRA and HRA to allow a clinical trial into the use of puberty suppressing hormones, sometimes known as “puberty blockers”, in children with gender incongruence. The clinical trial is sponsored by King’s College London and the South London and Maudsley NHS Foundation Trust and was proposed following recommendations of the Cass Review in 2024 to improve the evidence base regarding the use of such treatment in children with gender dysphoria and/or incongruence.

Jon Darby and Alice Walker, instructed by the Government Legal Department, acted for the Medicines and Healthcare Products Regulatory Agency.

Jenni Richards KC, instructed by Anita Rao of Hempsons, acted for the Health Research Authority.

Anna Biccaregui acted for the South London and Maudsley NHS Foundation Trust.

The full judgment can be found: here.