A hushed silence gripped the packed Hippodrome audience. Even the sweet-munchers, nose-blowers, throat-clearers and annoyingly loud whisperers kept quiet as the unblinking audience sat transfixed watching the sinister on-stage action edge towards its dramatic climax.

We were watching Sunset Boulevard, the spooky stage version of the film noir about a fading screen goddess and her dangerously unravelling mental state as her doomed comeback bid starts to slip through her expensively manicured talons.

On stage, said starlet – bitterly spurned by the man she loves – pulled out a gun and threatened to kill herself. Brushing this off as an emotional blackmail bluff, the man turned and walked away. Three gunshots pierced the air. The man lay dead. She shot him.

And at that precise moment, with the murderous film star still holding the smoking gun and a shiver still tingling the audience's collective spine, it happened.

An audience member's mobile phone rang.

Now, this would have been bad enough if said audience member had selected a standard ringtone for their phone. But no. It was a song. And not just any song.

So when their phone rang, the sound it emitted, the sound that shattered the dark, dramatic tension that had deliciously built up over the previous two hours, was a bawdy, shouty rap song called Baby Got Back by American rapper Sir Mixalot.

If you're unfamiliar with this number, it's a lascivious ode to ladies with particularly large posteriors.

And the opening line? "I like big butts and I cannot lie, you other brothers can't deny..."

Worse still, the owner of the ringing mobile had obviously forgotten which pocket his phone was in, so while he frantically checked his jeans, shirt and coat, we all had to listen to the song play on and on at high volume. As the poor lead actress stood motionless on stage waiting for the racket to cease so she could carry on her performance, these lyrics loudly reverberated around our oh-so-elegant theatre: "So fellas (yeah!) fellas (yeah!), has your girlfriend got the butt? (hell yeah!), so shake it! (shake it!), shake it! (shake it!), shake that healthy butt! ..."

How hard is it to remember to switch off your mobile phone or put it on "silent" if you're at the theatre or cinema? It's inexcusably bad manners not to. Even if you're waiting for an urgent call, put it on "silent" and "vibrate".

Some people seem to think it's their God-given right to receive phone calls whenever they want and sod everyone else. I wouldn't mind so much if these calls were important, but you just know the vast majority consist of inane prattle.

Hollywood actors Daniel Craig and Hugh Jackman hit the headlines this week for reacting angrily to an audience member whose mobile phone went off in the middle of their performance on a Broadway stage.

The Brit and Aussie acting duo were playing Chicago policemen in the play A Steady Rain, and – still in character – they barked repeatedly in American accents at the careless audience member while the phone rang and rang.

Ringing mobiles are the bane of many performers' lives. It must be so off-putting.

We survived perfectly well for generations without mobile phones – now suddenly it seems some people can't live without them, even for the duration of a play or film.

I've even been in the cinema a few times while a mobile phone has rung and its owner has proceeded to have an entire conversation while sitting in their seat.

And – of course – the rest of us were too scared to complain for fear of fierce retribution for our audacity to infringe the phone-call-taker's "right" to spoil everyone else's fun.