A "grammar vigilante" has been correcting apostrophes in the middle of the night on signs in Bristol for 13 years, it has emerged.
The anonymous man uses a homemade "apostrophiser" and purpose-built trestle to complete his work, according to The Telegraph.
This allows him to reach up to shop signs or road signs, where he then either adds an apostrophe or covers up one that is not needed.
He also ensures that he matches the colour and font used on the sign so that it does not look out of place.
The first apostrophe he ever removed was on a shop named "Amy's Nail's," removing the second of the two.
Other shops he has corrected have included estate agents and hairdressers.
The man told the BBC: "People might say what I am doing is wrong, but it is more of a crime to have the apostrophes wrong in the first place.
"I have felt extremely nervous. My heart has been thumping. I've got to make sure it's technically right.
"When I look at a sign and I have been the one that's done that and made it grammatically correct, it does make my heart swell slightly when I see the correct apostrophe."