A pre 1939 public information advertisement. If the cyclist was in a crowd I don’t think the image would be quite as unnerving, as a cutout and staring straight at you I can just imagine the words “are you my Mummy?” coming from the loud hailer.

‘Sounding a loud alarm through a loudspeaker clamped to the handlebars of his bicycle, a masked rider wheeled through London streets recently, like a modern Paul Revere, to test the efficiency of a new method of warning the public against sudden aerial gas attacks in war time. Equipped with gas mask and respirator, the cyclist broadcast warnings through a microphone built into the mask and wired to the battery-operated loudspeaker.’