On one of my near-daily visits to our local Waitrose last week I bumped into a pal as I emerged from the detergent aisle and set off towards the booze.

“Not having your free coffee?” said Cass, surprised to observe that unlike many of the shoppers I was without a cardboard beaker of the beverage clutched in the hand not holding the self-scanning device.

“I shall have it later,” I said, adding that the coffee – to which I am entitled as a holder of the My Waitrose card – would be drunk beside the customer service desk where the two espresso machines reside.

“I don’t go in for consumption on the hoof,” I said, “and especially not where food is concerned. I loathe seeing people grazing in the streets.”

Cass knew where I was coming from. “It’s an age thing,” he said, though he’s at least two decades younger than me. He meant we had been brought up with notions of correct behaviour – to walk on the road side of female companions, to remove our hats indoors or in the presence of women. Indeed, to wear hats at all.

Our exchanges over, I moved off to the till, for coffee and then for home, carrying in my shopping bag the free newspaper that is another valuable benefit of My Waitrose membership. Usually it’s The Times or Telegraph, but today I picked the Daily Mail.

Imagine my surprise – as they say – when I opened it and found on page 15 a why-oh-why? piece on the very subject addressed by Cass and me in our conversation. It was written by Gyles Brandreth who, to judge from the photograph accompanying his by-line, has finally ceased to present the appearance of an overgrown schoolboy. The headline read: “There’s nothing more vulgar than guzzling food in public.” A strapline above enlarged: “As more and more people eat on the street, trains and even at the theatre, it’s giving Gyles Brandreth indigestion.”

It was an experience in the theatre that had finally provoked Gyles’s explosion into print.

Visiting the Barbican for the Royal Shakespeare Company’s production of four of Shakespeare’s history plays, he was dismayed by how much very audible eating and drinking was going on around him.

“Behind me a lady was rifling through her handbag for her sweets. She did this continuously for the entire three-hour performance. Only during the interval did she stop.”

In front, a young men chomped his way through a very moist egg sandwich. I wondered how Gyles knew it was moist; the squelching, I suppose.

To the left, were women drinking white wine, rattling the ice cubes loudly in their plastic glasses.

Others were drinking water, from bottles equipped with teats “so you have to listen to lips smacking before the gulping and the gurgling starts”.

Gyles is not the only newspaper writer sounding off on this subject. Similar complaints about audiences have been made by Ann Treneman, the newly appointed chief drama critic of The Times.

One might have supposed, though, that she would have been well used to the spectacle of people behaving badly, since her previous beat was as The Times’s parliamentary sketch writer.

She is also – dare I say it? – from America, the home, I would have thought, of public scoffing, well, certainly of the hot dog and burger.

As one obliged to spend part of every week in the darkness of the theatre stalls, I too have suffered from the selfish indifference to others shown by some of my fellow audience members.

The most egregious example I recall was at the Mill in Sonning. A mobile telephone rang and rang during a performance and was then answered. Yes, answered. The woman culprit beginning what became a fairly lengthy exchange with the caller before the outrage of neighbours convinced her to desist.

The fare at the Mill is what might snootily be called lowbrow – comedies and thrillers – and as such attracts an audience that might otherwise be seated before the telly.

That some people mistakenly think that is precisely where they are explains why they are not put off from passing comment on the entertainment to the people they are with.

As I have long noticed, coughs and snuffles, a major irritant, are silenced when the action gets gripping. Strange but true.