I would have joined that class and I'd have been the first one caught

Not horror, technically. Absolutely horror, actually.

You know about the murder before you're two pages in. She tells you who, she tells you roughly how, and then she spends the entire novel making you understand it, which is a far harder sell than a whodunnit, and she manages it with room to spare.

What I love is the cold. Everyone in this book is freezing for most of it. Richard in that unheated warehouse room with the holes in the roof, putting on every jumper he owns, lying about where he's from, going to bed in his coat and waking up unable to feel his hands. I read that section in January with the heating on a timer and I have never felt so thoroughly clocked by a novel about rich people.

The group are appalling and I would have died to be let in, a horrible thing to notice about yourself at 34. Henry is the most frightening character I've read in years and he never does anything remotely supernatural; he just arrives, knows things, and stays completely calm about all of it. Bunny is written so precisely as a specific sort of loud sponging bore that I got genuinely irritated every time he opened his mouth, which I assume is deliberate, and it's a risk, because you spend a long time wanting him gone and then you get what you wanted.

The back half is where people fall away and I understand why. Once the thing has happened it becomes a very slow account of six people not coping, in bathrooms, in cars, at a funeral, and all the tension sits in what nobody says over breakfast. I found it unbearable in the good way. Dec asked why my face was like that and I told him someone is about to get found out, and he said "in the book?" and I said obviously in the book.

Things I'd knock off: the bacchanal, described afterwards and secondhand, is a bit much — the one place the whole thing tips over into silly for me. Camilla is a mood rather than a woman. And the long hotel stretch near the end has never once worked for me.

Also, not really a criticism, but I have never met anybody who read this and did not immediately want to learn ancient Greek for about a fortnight. I bought a Teach Yourself off eBay in a fit of it. It lives under the bed. Bertha sleeps on it.

My copy is the black one with the Greek lettering, it's been lent to four people and come back twice, and the spine is now at the stage where it flops open at the dinner party chapter on its own.

Nine. Read it in autumn, in a cold room, in a cardigan, and don't do the ending on public transport.