Newsreaders are on to something when they say this. It's the same thing that drives a lot of English lessons; you can be halfway through a book and only realise the magical power of the ending when somebody gives it away.
I was reading Lord of the Flies with a GCSE class once (and if you don't want to know the ending of this and several other works of literature, look away now), and tensions on the island were beginning to mount when Darryl interrupted with the words: "Piggy dies."
Never mind that a sensitive reader can foresee the tragic inevitability of Piggy's death. Never mind that Darryl lacked confidence in English, so this nugget of fact - gleaned from an older sibling - gave him his moment of glory. Never mind that half the class didn't seem that bothered. I minded, the remaining students minded - and probably William Golding would have minded too.
Dealing with such spoiling tactics isn't easy. Most schools don't actually have a rule against Ruining a Class's Sense of Narrative Uncertainty. It may even be a problem confined to English lessons. I doubt maths teachers fume when a voice calls out "37" before the end of a sum. I can't imagine a chemist raging at a premature cry of "copper sulphate". But what fuels at least some of our reading is that old dilemma from A Question of Sport:
"What happens next?"
As a teacher, I've known the fate of some of these fictional folk for years. But it's no bad thing to be reminded that the ending is still news to new readers.
I was never more aware of this than when I once took a class to see King Lear in Stratford. They had an understanding of tragedy, so the odds weren't looking good for Lear. But we hadn't finished the subplot, where the disguised Edgar slays his half-brother Edmund in a duel. When this masked hero strode ready on to stage, a ripple of excited speculation went through our part of the theatre, guessing in whispers who this was. "Isn't it obvious?" I was thinking, when I suddenly grasped what Shakespeare's first-night audience must have felt. Like my students, they had clues, hopes and theories about the man behind the mask; but they didn't yet know.
Beginning a text again, I try to recall that the possibilities are endless. Hamlet might not die; Macbeth might not listen to his wife; and the beasts of Animal Farm may triumph.
Darryls are still not allowed to spoil it, but equally, neither am I. We all need fresh eyes for the journey.
John Gallagher teaches English at King Henry VIII school, Coventry