Q. The other night, as I arrived at the John James exhibition on Fulham Road, I stopped to say hello to an old friend standing outside. We had exchanged only a few words when the man next to him suddenly addressed me in sneering tones: ‘Are you having a senior moment?’ It is true I had failed to recognise him, though he was once very handsome and I had attended his wedding, but I hadn’t seen him in the 20 intervening years, during which time he had gone grey and even grown a grey beard and moustache.