Is that a tall, dark, and handsome man standing over there? Or a tall, dark and handsome man? The vexed question of commas, where to use them and where not to, was raised at Hay festival by the linguistics academic David Crystal.

Both of the above are correct, he said, but he criticised the Department for Education for not realising that, and for allowing exam boards to wrongly penalise children. He said the current guidance for schools “leaves a huge amount to be desired, especially in areas of punctuation.

“There is a tendency in the question setters of linguistic naivety; they are simply not aware of the complexity of some of the decisions they are asking the kids to make.”

The comma and where to use it is a case in point. The debate over whether to put a comma before the “and” in a list has been around since the 18th century, Crystal said. In the 19th century “publishing houses decided they were going to sort it out and … made different decisions”.

Oxford University Press decided it should be in, and in such cases it is now called the Oxford comma or serial comma. They reasoned that each adjective before the noun was of equal importance, so should all have a comma. Cambridge University Press, however, decided it should be left out. This raises fierce debates, Crystal said, but both examples of usage were correct.

He said the Oxford comma had been banned in the latest guidance to teachers, so any child writing “tall, dark, and handsome” had to be marked incorrect. That meant Oxford comma fans (Crystal counted himself as one) were now using the wrong punctuation.

Crystal, honorary professor of linguistics at University of Wales, Bangor, was giving a talk about his latest book Making a Point: The Pernickety Story of English Punctuation. He admitted he rarely gets worked up about the things which infuriate lots of people – even the multiple use of exclamation marks!!!

He is professionally interested in the changing use of punctuation, including how full stops are not used anywhere near as many times as they were in the 19th century.

What really irritates him, he told the Hay audience, was what he called Radio 3 syndrome, when after a piece of music the presenter drops his or her voice at the end of a sentence. “That was Symphony No 3 in D major by [inaudible]. What?”

Or perhaps that should be: “What!”