Who left food in the fridge? The rise of the 'Dark Knight' workplace vigilante

Self-appointed enforcers, keen to report colleagues for misdemeanours, are a common - and potentially costly - issue for organisations, survey finds

They are the Dark Knights of the office: lone vigilantes who police the workplace, ever watchful for heinous crimes that cannot go unpunished. Woe to those who step out of line and return from break two minutes late, leave food in the office fridge too long and fail to refill the photocopier.

More famous for populating Wild West gangs, superhero movies and the New York subway, vigilantes are now found in all corners of professional life, a new survey has found. Over the course of their careers, more than half the people surveyed had experienced at least one "Dark Knight employee", as researchers dubbed them, while 18% said they still worked with one.