‘When people ask me what I do, I reply, “Nothing”, ’ Isaiah said, apropos of no particular subject when we were putting on our coats before walking back from the Garrick where we had been lunching together.

I said: ‘I saw your step-grandson the other day in Paris – young Strauss – and he asked me about your sex-life: ‘ “Lurid,” I hope you answered.’ To which I replied, ‘I told him I’d known you for a long time.’ Isaiah then asked me how and when we had first met – which in fact was at Oxford in the mid-1930s.

He looked along the clothes-hooks for his hat. He chose the wrong one, and, as we descended the steps into Garrick Street, he discovered his error and, in some anxiety, returned to the hooks as if in search of a lost child.

As we sauntered towards St Martin's Lane I commented on the elaborate and alluring elevations of the tall Victorian buildings, and, more generally, on the charms of this part of London. ‘Yes, yes,’ Isaiah bumbled, not dismissively, but as if it were self-evident.

‘I suppose we could go via Chinatown,’ I said. Isaiah gave a grunt of approval and we set off towards Charing Cross Road, which we agreed, as we crossed it, was not what it was when it enjoyed the reputation of a book-browsers’ paradise. Isaiah is a keen browser, not just of books. Someone once told me of an hour or two he had spent with Isaiah browsing amongst the medicines in John Bell & Croyden in Wigmore Street, a passion that may reflect his tendency to hypochondria; but also his love of shopping.

He alluded to this love later in our walk when we came to an ironmonger’s shop whose windows were full of paints, coils of string and hand-tools. Isaiah stared at the window with rapt attention as if he were contemplating a display in some oriental souk. I suggested we should enter. He replied that he wanted to buy a rubber tip for the end of his umbrella, which he then lifted up to show me. We entered the shop and he was immediately taken by the array of little wooden drawers behind the counter, each bearing a label. He seemed to be in no hurry to indicate his intended purchase. Nor did the shopkeeper show any impatience.