When I was in Cardiff, playing with the National Orchestra of Wales, they said they get letters from people complaining if they're smiling during the concert. Nuts, isn't it? As if you have to respect the solemnity of the music by not smiling. Music is this joyful thing that enriches our lives, and you're not supposed to smile?

This was supposed to be yesterday. I was sitting on the Cardiff/London train, supposedly about to write this very column, and realising something quite terrible. My head was entirely empty. A vast echoing void. Bigger on the inside, but with nothing in it. You could drop a pebble in my brain and wait for an hour to hear it land. No actually, you couldn't - that would be aggressive and unhelpful, so keep your damn pebbles to yourself.