A house divided against itself cannot stand. We have all sensed that, surely, in this time of more or less ungrudging solidarity with the wider world. For the rest of our lives, however, we'd be very grateful if the first Saturday in May can mean exactly what it has reliably meant before today. In recent weeks, we've all been buying into the idea of sacrifice for the greater good. In the process, we've been reminded how precious are those routines and rituals, such as Derby day, we previously took for...