How did prisoners build a hidden radio?

Prisoners in Colditz Castle ingeniously built a hidden radio from spare parts smuggled in and scavenged within the prison. The French prisoners managed to sneak in essential components like valves, while other parts were creatively sourced from items around the prison—essentially cobbling the radio together with whatever they could find, akin to bottle tops and bits of string.

This secret radio, hidden in a specially constructed compartment in the attic, allowed the prisoners to listen to nightly news bulletins from the BBC World Service. They transcribed these bulletins and disseminated the news throughout the different prisoner messes. This effort was crucial for maintaining morale, keeping the prisoners connected to the outside world, and informing them about the war's progress, often more accurately than their German captors 1 2.

Despite suspicions from the guards and numerous searches, the radio was never found during the war. It remained hidden until years after the castle was liberated, discovered during routine maintenance in the attic where it had been originally concealed 1.