Quentin Blake gets me thinking. I’m sure that’s because he’s a great artist, and great artists excite the brain as well as the senses. I was at Sotheby’s (London) for a charity event in support of the House of Illustration last December when the actor Peter Capaldi read extracts from Dickens’ A Christmas Carol. During the reading Quentin Blake executed two original ink and water colour illustrations of the story – in real time. They were later auctioned in support of the char