"So here I am," Ian McEwan's new book begins, "upside down in a woman." The English writer has always taken a keen interest in the condition of human beings who have been stretched to breaking point and beyond, but his 17th novel takes him right into the core of the human story, for Nutshell is narrated by an unborn baby.

The idea was conceived a couple of years ago, when McEwan was talking to his heavily pregnant daughter-in-law. "We were talking about 'the baby' – they didn't want to know whether it would be a boy or a girl," he recalls. "And it flitted through my mind; what would it be like to be overhearing all this? A little later I was re-reading Hamlet, and thinking how helpless Hamlet was, and it crossed my mind again that the most helpless human being is the one that's about to be born."

Shortly afterwards, trapped in a spectacularly dull meeting, the first sentence of the novel arrived in his mind, pretty much fully formed. There it was: the novelist’s “aha” moment. “It was the challenge of writing a revenge drama from the point of view of the most helpless human you could conceive.”

For a writer the drawbacks of such a restricted narrative perspective are obvious but, McEwan insists, there are compensations. “He’s always in the room. And he actually has a very privileged point of view. He hears the pillow talk. He’s in bed with the lovers. So, novelistically, he’s quite ideal. He overhears everything, and no one suspects a thing. It’s a bit like deciding to write a villanelle, or submitting to the very strict rules of a sonnet that has three quatrains and a couplet – it’s a set of problems. But they were rather fun to solve.”

Shaped by his father

This, the reader swiftly discovers, is one well-informed baby. He is well up on Kant and Confucius and has a working knowledge of the Higgs boson. His vocabulary includes “solipsism”, “Leviathan” and “aetiology”.

He's also a bit of a Sancerre snob. Much of his knowledge has been gleaned from the audiobooks beloved of his expectant mother – among them a 15-part series entitled Know Your Wine – and podcasts on everything from maggot farming in Utah to the physics of tennis.

His ideas about his mother’s appearance, meanwhile, have been shaped by his father, a poet by the name of John Cairncross, who likes to recite his work aloud – especially when it describes his beautiful wife’s “wild curls” and “shoulders the white of apple flesh”.

But here’s the rub: baby’s mother (Trudy) is having an affair with baby’s uncle (Claude). Which would be bad enough for baby, who is forced to get up close and personal with their enthusiastic lovemaking – “I’ve no choice, my ear is pressed all day and night against the bloody walls” – but there’s worse: he is also a witness to the treacherous pair’s plan to kill his father.

If the names haven’t given McEwan’s game away – Trudy and Claude, aka Gertrude and Claudius? – there are further clues in the book’s title, and its Shakespearean epigraph: “Oh God, I could be bounded in a nutshell and count myself king of infinite space – were it not that I have bad dreams.”

Is Nutshell, then, a novelistic recasting of Hamlet, in the manner of the Hogarth Shakespeare series currently being produced by a rival publisher? "No. It's a sort of raising the hat," McEwan says. "I started in 2014, and to be quite honest I'd completely forgotten that we were running towards a significant anniversary. It was only when I was about halfway through, in 2015, that I heard someone mention that Peggy Atwood was doing a Shakespeare, and then I heard that Howard Jacobson, or someone else, was doing one, and I thought, Oh my God.

“But it doesn’t worry me. I mean, let everyone pile in. Those of us who write in English – whether we like it or not, and whether we know it or not – live in Shakespeare’s shadow. He’s so formative for the English language that it’s right, I think, that he should be celebrated or railed against or whatever.”

While Hamlet formed "a sort of skeleton plot" for Nutshell, the play very quickly fell away as McEwan's storyline developed. Certainly, Shakespeare never concerned himself with the excesses of the London property market, a central motif in Nutshell.

"But still, it derives its title from Hamlet, and it's always slightly working with it or against it. It's always aware of it, I suppose. But once I was launched I was in another realm," he says.

The fact that his precocious narrator listens to so many news broadcasts allows for plenty of rumination about the state of the world beyond the bedchamber. And it’s not good. “Things always seem to be getting worse,” McEwan agrees. “But we’re probably wrong about that. Let’s take a specific issue – of terrorism in western Europe. Fewer people died in terrorist attacks this year and last than they did in the mid-1970s. So I think it’s part of our nature – especially among intellectuals – to think we live at the end of time, and in the worst of times. It’s a sort of reflex. And it’s not an unreasonable one, because we look for the things that we think we can solve – and then despair about it. But yeah. In my pessimistic moments I think . . . well, take climate change as an issue. The state of things has never been worse and has now exceeded expectations. I was just reading ice-melt figures for Antarctica and Greenland yesterday. Filled me with horror. So on that front I think we are staring down the barrel of a gun.”

After Brexit, McEwan wrote an article for the Guardian that was, effectively, a riff on the moment in James Joyce's Ulysses when Stephen declares that "history is a nightmare from which I am trying to awake". Has he awoken yet? "I'm still in denial," he says. "I still cling to a notion that it's not gonna happen. That it will quietly unwrap itself. That the EU might well loosen up on free movement of labour. That we'll be in recession, public mood will have changed, what's on offer when Article 50 is negotiated will not satisfy those who wanted to leave.

Upending ourselves

“I suppose my objection is that these are such massive realignments that to run them on a 4 per cent majority is against all notions of parliamentary democracy. If we were rewriting our constitution, we’d expect a two-thirds or a three-quarters majority on any referendum. I never thought we should be upending ourselves so thoroughly with a plebiscite.

“Some of my friends who wanted to remain have knuckled down, and probably they’re realists. I still cling to the notion that it is just a bad dream and we will wake up from it.”

Into a world, though, that features Donald Trump as president of the US?

“I think he’s toast,” comes the brisk rejoinder. “I think he’s Trump on toast. My fantasy is that, in a few years’ time, we’ll talk about him almost in fond remembrance as, again, a terrible dream which is now over. I think he’s simply too awful to succeed.

“But then, I said that about George W Bush. And I said it about Ronald Reagan – who, in retrospect, looks like Descartes and Yeats rolled into one. Ask me again in November.” We might just do that. Unless, of course, we’re too busy raising a celebratory glass. Of Jean-Max Roger Sancerre, naturally.

Nutshell by Ian McEwan is published by Jonathan Cape

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