New documentary explores Gibraltar’s underground tunnel network

A new documentary charting Gibraltar’s vast underground tunnel network and its military history has been released, highlighting the Rock’s strategic importance and drawing on local expertise.

The film, entitled Inside Britain’s Secret Underground City, follows documentary filmmaker Cole Robinson as he travels to Gibraltar to explore the extensive system of tunnels carved deep into the Rock.

Initially constructed during the Great Siege and significantly expanded during the Second World War, the tunnels formed a concealed military environment of hospitals, command centres, ammunition stores and living quarters, designed to allow Gibraltar to withstand prolonged conflict.

The documentary examines why Gibraltar, despite its small size, has been so heavily fortified over centuries, exploring how its geography made it a strategic priority for Britain and why substantial resources were invested in creating one of the most complex military tunnel systems in the world.

A key contributor to the film is Dr Geraldine Finlayson of the Gibraltar National Museum, who provides historical insight into the development of the tunnels and the long process of militarisation of the Rock.

Through her interview, Dr Finlayson outlines how successive periods of conflict shaped Gibraltar’s underground landscape and how the tunnel network evolved in response to changing military needs, grounding the documentary in local research and history.

While rooted in military history, Inside Britain’s Secret Underground City is also intended as an educational resource and is set to be shown in schools and colleges across the UK, with screenings accompanied by question-and-answer sessions with Mr Robinson.

The documentary is available to watch online, with further information about the filmmaker and his work available at www.colerobinson.co.uk.