This evening, Sir Simon Rattle brings the Berlin Philharmonic Orchestra to the Proms for their second concert this season. After they have played Messiaen’s Éclairs sur l’Au-delà there will, no doubt, be loud cheers. That is the norm when such a great orchestra and conductor perform.

That will not, however, be the only non-musical noise. Something else has also become the norm — kerfuffle. Not just after but during the performance. I have been to nearly a dozen Proms so far this year. Not one has been free from someone near me either chatting to her neighbour in the middle of a piece, conducting along and tapping his foot, or simply getting up to leave when the fancy took him, even in the pianissimo.

People in audiences today have been so indoctrinated with the idea that they must fulfil themselves and act on their desires, that they now behave as if their wants are all that matter. Feel like leaving? Then leave. That it might disturb three thousand other people is of no consequence.

I have been going to the Proms for more than 25 years. For 15 years, as a season-ticket holder, I would stand in the arena. I gave up because — contrary to myth — promenaders are among the most undiscriminating and noisy audiences anywhere. Sitting in the stalls, there was much less risk of encountering a couple snogging, a man unwrapping his foil-covered sardine sandwiches or a young woman reading a book and laughing at it at in the hushed silence of a Bruckner symphony — all of which happened around me in one concert.

It seems to me that audience behaviour has, however, reached a new low. There is now no escape. On Friday, for example, I had to turn to my neighbour and ask him not to wave his arms in the air pretending to conduct Bruckner’s Seventh Symphony. The job was already being done by Bernard Haitink; he did not appear to need the assistance of a man in the stalls. No sooner did that distraction cease than, in the middle of the slow movement, a couple barged past everyone on my row as they made their way out of the hall.

Perhaps the best response to such behaviour was from the pianist, Andras Schiff, at the Edinburgh Festival in 2001. Confronted by ringing mobile phones and a man who seemed to be auditioning for a place on the Olympic coughing team, he got up after the slow movement, announced that he could not continue amid such cacophony and that he had no choice but to pause, and walked off the stage.

It is too much to hope that the culprits were shamed because the onward march of the ignorant gathers pace with every passing day. The cause of their misbehaviour is ignorance: ignorance of etiquette, ignorance of decent behaviour and ignorance of the purpose of live performance. I do not suppose that these people wilfully set out to disrupt others’ enjoyment. They simply do not understand that live performance is different from listening at home, and thus our behaviour must differ, too.

An audience may be composed of thousands of individuals but they come together to form something of a whole. Disruption of that whole cannot but break the spell of performance.

It is not just music which is ruined by these selfish ignoramuses. The theatre also suffers. At a performance of David Mamet’s Boston Marriage which I attended in the small Donmar Warehouse, a woman’s mobile rang repeatedly. One can perhaps forgive a single ring, when the perpetrator has forgotten to turn the phone off. But this seemed never to stop. I loathed the play; but the evening was worth it to witness the actresses, Anna Chancellor and Zoe Wanamaker, each give the culprit a stare so cold that I hope she still wakes in the night in a sweat.