Being honest about it, most teachers would recognise that they, too, are not immune from similar mistakes, for daily exposure to bad spelling and ropy maths might undermine the stoutest foundation. At primary we had the daily prayer followed by an hour of mental arithmetic before an hour of formal. The legacy today is that, when pupils check lists of marks, they have occasionally looked askance at me when I’ve provided an answer with no visible means of support - “how did you do that?” Mistakes, though, can affect all of us - the great and the good in equal measure. Even the Scottish Qualifications Authority hasn’t escaped. Imagine the horror. New corporate logo designed, new offices, new staff, new qualifications, new contracts of employment, new executive, new forms (replacing the same old ones that had Scotvec at the bottom).

Yet turn over the form and clearly written is “Do not use PENCEL or RED INK”. Will the chief executive resign or will he be gunning for some other scapegoat?

The inadvertent errors are the best. This year’s prelim marking was enlivened by the girl who wrote about Long Rob of the Mill, the conscientious objector in Sunset Song - he stuck to his guns and refused to go and fight - while cultural misunderstanding allowed a Chinese boy studying Edwin Morgan’s “King Billy” to write that there was a violent Glasgow gangleader called Billy King.

A recent Jordanhill languages student shocked his listening teacher by instructing the class that Bastille Day was a public holiday held in France to recognise the end of the Second World War, and our department once had a supply teacher covering an eight-week absence in learning support who spent all his time feverishly communing with the Apple Mac. Only when he left did we find a copy of his father’s will and the first act of the play he’d written while he’d been with us.

Sometimes the confusion between similar sounding words allows listeners to ignore the message in their glee to hunt the solecism - thus “flaunt” and “flout”, “prostrate cancer”, “procrastinate” and “prevaricate”, but my personal favourite came years ago when Tommy Docherty was asked what he would do with football hooligans to deter them repeating their offences. “Capital punishment,” opined the Doc, “would soon stop them wanting to do it again.”

Teachers can be caught by a failure to update their own general knowledge. I know of the principal teacher of history who went to the depute head some years back to try to trace the David Bowie whose name disfigured the desks in his classroom, and there’s a Bart Simpson registered to do a Scotvec module in “Investigating Career Opportunities” because his teacher wasn’t alert enough to popular culture on the day of enrolment.

Pride of place for the monster error goes to my neighbour - a primary teacher - who had requested a meeting with the parent of a girl in the class whose progress was of concern. The appointment was made, the father duly arrived, and only then did the awful truth dawn that of the two pupils called Marie in the class the dad sitting opposite who had been summoned to the school was the parent of the wrong one.

Peter Maclaren