Gibraltar is stockpiling emergency medical supplies in hidden tunnels below its iconic Rock in case Brexit negotiations over the border with Spain fail.

After Brexit, border controls were waived for Gibraltarians and Spaniards as an interim measure to buy time for the talks, which have dragged on for three years.

Spain has stepped up pressure on London to accept EU border demands since Sir Keir Starmer surrendered sovereignty of the Chagos Islands earlier this month.