I have never liked going to a concert or theatrical experience where the first thing you are told, by a disembodied voice-over, is a series of don’ts.

Don’t take a video. Don’t take pictures. Switch your phone off, or better still, place it in the convenient bucket of water we have provided so you can never use the horrible thing again.

I have seen people try to video a bit of a performance and ushers leaping across seats like mountain goats to stop them, which is much more disturbing than the videoing itself.

I had a strange experience of this in London in August, when we went to see the musical Cabaret at the Playhouse Theatre near the Embankment. They’ve turned the theatre inside out, so the audience enters through the stage door and then exits through the main foyer. As we stood outside in the rain, we were treated to quite a severe talk from an usher, who informed us that we were to TAKE NO PHOTOS AT ALL...