In 2011 a man was shot dead at a Latvian cinema after reportedly eating his popcorn too loudly during a screening of Black Swan.

I wouldn’t go that far, but, on a recent visit to the theatre, I felt like screaming at a woman sitting nearby who insisted on rummaging about in a packet of biscuits during the performance.

We had never before been to the theatre as a family - the cost being massively prohibitive - and we enjoyed it, but the drama needed close attention, without the distraction of rustling wrappers.

Not only that - someone’s mobile phone rang at a key moment, which as well as distracting the audience, could also have been disrupting for the cast. And in the second half someone in front of us was munching their way through a tub of popcorn.

The play began at 7.30pm and ended at 9.30pm, with a 20 minute-or-so interval. I can’t understand why people can’t last for such sort periods of time without food or drink, and why when they do eat, does it have to be ‘loud’, crunchy food - which cinemas and theatres should not be selling.

I realise that people literally can’t live without their mobile phones, but even I, with my limited technological know-how, can switch a handset to silent. I also can’t grasp why adults can’t sit quietly - like naughty schoolchildren, some can’t stop chatting.

Sadly, I don’t think people care. I could no more sit in a quiet auditorium eating crisps than run naked across Headingley cricket ground during a Test Match, but many people don’t even register the impact their actions will have on others.

It ‘s the same when I travel by train. Quite often, fellow commuters put half full drink cans or apple cores on the table in front of them, then leave them behind when they get off. I often stare after them in disgust. I’ve seen parents watch children spread all manner of sticky sweets and pop across the table.

People are becoming ruder than ever. If they want to get past you they don’t say excuse me, but barge into you, glaring. The other night, in Marks & Spencer, I was waiting along with other people, while a member of staff reduced some expensive desserts. Instead of taking just one or two, the woman at the front of the queue filled her basket with about ten items, leaving barely any for the rest of us. The man behind me barked a few choice words, but she didn’t bat an eyelid.

Increasingly, people live in worlds of their own. They look after number one and don’t care how their behaviour affects others. It’s got to the stage where it comes as a shock when someone is polite.