Flying LHR to LAS in 62K, after an extraordinarily large JW Black, my foot bumped against a panel to my left. Turns out it has hinges and a sprung door and conceals a secret compartment.

Not wanting to cause any alarm, I didn't get on my knees and rootle around, but from what I saw it seemed to contain wires.

Apart from being intriguing, does anyone know what this secret compartment is and its purpose?