Fairy lights
Deceptive lights seen at a distance (fairy lights, will-o'-the-wisp, ignis fatuus, bog lights) that lure the unwary toward danger in folk tradition. In Taylor's writing the image marks the speaker's first glimpse of something beautiful that will prove destructive, with the danger already encoded in the source folklore the speaker chooses to ignore.
The deceptive allure of something visually inviting but harm-bearing - the speaker registers the warning encoded in the folkloric register and follows the lights regardless.
Appears in 1 song
“I saw in my mind fairy lights through the mist”
The fairy lights are warning signs, deceptive lights that lure the unwary in folklore traditions. The speaker sees them through mist (literal London fog and figurative clouded judgment) and walks toward them anyway, beginning the doomed relationship.