Ten years ago, Lynne Truss published Eats, Shoots and Leaves: the Zero Tolerance Approach to Punctuation. It was doctrinaire about commas, semi-colons, dashes and other diacritical marks, and it seemed to signal the end of the line for the Grocer’s Apostrophe – you know the kind of thing: “Apple’s and Pear’s 75p a pound!”, “King Edwards Potatoe’s £1.99 a kilo”.

When Ms Truss revealed that she habitually carried a black marker pen and Tippex with which to add or remove apostrophes on road signs, people began to refer to “grammar bullies”, even “grammar fascists”. Others considered such actions entirely justified and quoted Ms Truss: “Proper punctuation is both the sign and the cause of clear thinking.”

A decade later a new row over the naming of Princes Street, the main thoroughfare in Edinburgh’s city centre, has flushed out two shadowy organisations dedicated to the airborne comma.

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The Apostrophe Vigilante encourages Twitter followers to write in with heinous examples of apostrophe abuse: a pub sign reading, “The Grand Victorian for speciality coffee’s”, “Lets Dance” seen on a Love Heart, “There are a thousand ‘no’s’ for every ‘yes’,” seen in an Apple commercial. “Apostrophe fails” are recorded in schools, libraries and airports (“Due to Construction and space constraint’s, we are temporarily unable…”)

The Vigilante, which has been around since 2008, is run by two women called Brid and Hannah. They are punctuation sticklers, though guilty of sloppy writing themselves (“There is absolutely no doubt in my mind that people who use apostrophes incorrectly is just taking the proverbial biscuit.”) They’ve called on Edinburgh councillors to restore the original name of Princes’ Street, so called after George III’s eldest sons, the Prince of Wales and Prince Frederick, Duke of York. It stayed Princes’ Street until the 1830s, when the apostrophe simply disappeared.

The Apostrophe Protection Society was formed in 2001 by a former sub-editor called John Richards. Its modus operandi is less violent that the Vigilante’s: Richards just sends a polite letter to offending businesses, explaining the rules of apostrophe usage. The Princes Street business, however, has got him riled. He calls the current name “incorrect, lazy, ignorant and appalling” and thunders: “Princes Street alone implies nothing.”

Meanwhile, the outside world looks on in amazement at the fuss caused by tiny marks. When a row broke out three years ago in Perth about correct usage, the West Australian newspaper carried the headline: “English speakers split over a squiggle.”