Has anyone seen our chairs? They were the collapsible sort, last seen in Covent Garden piazza. My son William and I had been queuing for Tristan und Isolde. I’d never intentionally queued for anything before, but some deep British instinct told me what to do. ‘Take chairs,’ it whispered, ‘and a Thermos.’

But the latter advice came too late. Instead, we bought a Sunday newspaper with vouchers for Starbucks. When we came out of the box office, we had not only lost the chairs, but two copies of The Observer.

Later, William and I agreed they had been worth the sacrifice. We got our tickets; we could see very nearly all the stage, except, eccentrically, the part where the major action took place; the singing was electric. If only William had been in Frank Johnson’s position, however.

The man whose elegant Parliamentary sketches have just been collected in Best Seat in the House went to what would now be called a ‘bog-standard’ school in Shoreditch. But it supplied children for the opera. At William’s age, 14, Johnson played one of Norma’s infants, clasped to Maria Callas’s bosom. ‘Too bigga,’ lamented Ebe Stignani, playing, at 52, the young temple virgin Adalgisa. But, as Callas remarked, even the great Stignani had to abide by British employment laws.