John le Carre is guilty of it. So are Scott Turow, the bestselling American author, and Jeffrey Archer, the politician and novelist who now has designs on the mayoralty of London, writes Clare Dean.
Their crime? Abuse of English, using cohorts instead of colleagues and may have when might have would have been correct.
It is a sin that unites journalists, politicians, academics and Royalty. But it is one highlighted at the accuser's peril, as John Honey, a long-time critic of the English-teaching establishment, knows.
He is in no doubt that people will hunt through his latest book, Language is Power, for mistakes which they will seize upon "gleefully". But Professor Honey, who until last year was Professor of English at the Osaka International University in Japan, is unrepentant.
He wants a return to the basics and believes that what is needed is a "language tsar" and a committee of the well-educated to advise on the correct use of English.
Celebrity authors Malcolm Bradbury and PD James would be on Professor Honey's list of members, as would Robert Burchfield, past editor of the Oxford English Dictionary. Although he has not ruled himself out, Professor Honey is off to a teaching job in Botswana.
The committee would issue directives and rules of guidance which would be taught to children in schools and made accessible through reference books in public libraries.
An important task, he suggests, would be to establish the use of a unisex pronoun to replace he or she and his or her.
Ideas to date have included ne, en, thon, hi, le, ip, ir, ons, e, hesh, po and em.
Then there is the painful-sounding "t-glottalling" - dropping the t mid-word as in "a be(tt)er bi(t) of bu(tt)er" - a crime first attributed to Cockneys, who are also blamed for making l into a vowel, so that Walter becomes Water, milk miwk and St Paul's St Paw's.
Professor Honey claims there is a generation of schoolchildren which regularly speaks ungrammatically and that even young university professors and teachers now speak "estuary" English.
He blames the decline of Latin for the loss of the true meaning of decimate - the taking of one in 10 - and gripes about the substitution of reticent for reluctant and the "ignorant" use of cohort (a group) - instead of colleague. Le Carre, an Oxford graduate with a first in German, and who once taught at Eton, was guilty of this last error twice in The Russia House, says Professor Honey.
He wants radical reform of spelling, such as redd for the past tense of read. "It is odd to have a University of Reading, since all universities are supposed to be about reading," he said.