The study, which saw 1,000 UK adults quizzed by LED Hut, found almost a quarter (23%) of people are afraid of the dark.
Of those, 65% admit it's a fear of potential intruders that spooks them the most, with close to half (47%) suggesting true-crime documentaries were partly to blame for their desire to keep the light on.
So extreme is their fear, in fact, that a fifth of those surveyed said they check their bedroom for unexpected guests before they get into bed, with 18% even checking inside cupboards and wardrobes to make sure there are no nasty surprises hiding inside them.
The hallway light is the one most likely to be switched on (according to 59% of Brits, at least), with 28% revealing they prefer to keep a lamp in their bedroom switched on whilst they slumber.
Just over one-in-ten (11%) leave their main bedroom light on each night, whilst 21% like to sleep with the television switched on.
Speaking about the findings, Paul Garner, marketing director at LED Hut, observed: "Whether it’s a fear of being alone, intruders or darkness itself, it’s surprising to see how many adults sleep with the light on – claiming to be scared of the dark. Often these are slightly irrational fears stimulated by television dramas or being home alone. However this can be caused by deep-rooted issues relating to anxiety".