There have been exhibitions, indeed even a whole museum, dedicated to cleanliness: the Deutsches Hygiene Museum in Dresden, for instance (image 9), which was founded for the purpose of public education in hygiene and health, but which later embraced and diffused racist theories during the Nazi era. Yet there haven’t been many – or any, as far as I’m aware – devoted entirely to dirt. It’s all around us, yet historically we seem to have considered the subject unworthy of serious cultural examination. And the reasons for avoidance are just as interesting as the filthy matter currently under the microscope at the Wellcome Collection (see theartsdesk's review).

A few years ago my brother and I were stuck in a traffic jam somewhere in London and a Rolls Royce drew up next to us with an elderly Asian gentleman at the wheel. He turned to us both and smiled sweetly before gliding on. For a blink of an eye, the driver morphed into our dad who died 20 years ago. My brother and I turned to each other and both said out loud, “Great Expectations.” It was our father’s dream to come to London and end up with a Rolls Royce and both myself and my brother mentally saluted the Asian gentleman’s smug realisation of our father’s ambition.

Christmas movies, like seasonal in-store promotions, really are arriving earlier every year. But despite being released before this month’s Catherine wheels have even started spinning, the new Disney version of A Christmas Carol has about it the desperate whiff of an end-of-line knock-off grabbed from a depleted branch of Argos just as the shutters are falling on Christmas Eve.