‘I’ve never really read any science fiction,’ she confessed. ‘Though we used to have quite a big section in our first shop, didn’t we, Barney?’

The sound of my name gave me a bit of a shock. I was surprised to discover I was still in the room. ‘Yes,’ I said.

Fitzpiers was appalled by Sharon’s admission. ‘You’ve never read any? Then you must. I’ll write you out a list.’ And on the spot he filled both sides of a serviette with writing, folded it and handed it to Sharon who put it in her bag. For all I saw of it it could have been a set of detailed instructions for getting to Fitzpiers’s flat.

‘In a hundred years from now,’ he continued, ‘this will be the literature the twentieth century is remembered by. The domestic novel will be forgotten. Who will care then about lovelessness and infidelity in Belsize Park?’

‘Who cares now?’ said Sharon. I could see that she was already half way towards being an SF addict.

‘Precisely,’ said Fitzpiers. ‘Who cares now? That’s not where we live any more. Science fiction has as its subject all the current threats and challenges to man: war, supersonic travel, television, metaphysical uncertainty, computers. It can make art out of the thrust or the waste, the dreams or the detritus of a technological civilization.’

I asked Rowland Fitzpiers if he wanted another milkshake. When I returned I found him explaining to Sharon that all the great nineteenth-century novels were in fact science fiction.

‘Take Dr Jekyll and Mr Hyde. The first fictional attempt to explore the workings of the unconscious, under the pressure of contemporary scientific investigation. What’s the most potent symbol in Dickens? The train. What’s Heathcliffe if not an alien, a visitor from another world, a child of the new scientific revolution? Even your own Thomas Hardy is as much upwardly mobile Darwinian as he is contented countryman. Everything struggles to survive in Hardy, precisely as the scientists said it does. Science fiction, you see. The central metaphor for Tess’s confusions is the threshing-machine, superintended by one who has the appearance, you will remember, of a creature from Tophet, another world. Pure science fiction. If it was called The Alien From Tophet instead of Tess of the D’Urbervilles you wouldn’t have the slightest resistance to the idea.’

Sharon was already not evincing much resistance, but I felt that I ought to demur, or at least put forward an amendment, if only for the look of the thing. ‘Funny you should latch on to the threshing-machine,’ I said, ‘I think the Marxists do the same.’ I wasn’t, as you might say, pulling any punches. This was Harrods, don’t forget.