Many years ago, when Child Number One was very small and I still lived in London, my dear friend Ms S and I used to frequent any number of playgrounds to occupy our children and to fill our days. This was in an era long before the iPhone became ubiquitous, when it was still possible to keep one eye on your child and the other on your adult companion. We would while away the hours chatting about our children, the world at large and of course, the people that surrounded us in those playgrounds. We would find ourselves jealous of the parents who might have brought a paper or a book, because their children were old enough not to require the endless supervision that ours did. However one group always stood apart, the London nannies. They represented a fabulous cross cultural mix of languages and attitudes that reflected the city in which we lived. It was a total ‘never the twain’ situation where there was a clear divide between parents and staff. Ms S was soon to return to work, so we would observe what we believed to be the type of nanny that she might require and look on in horror at those nannies who neglected their charges or indeed, even left the playground with a four year old in it, to nip home. We saw it all in those years, but never once did we see a ‘Louise’.

In late 2012, for those of us with children, there was an unforgettable news story that came out of the US, namely the murder of the Krim children by their nanny in New York. If you don’t remember the press surrounding it, the story went something like this: a mother returning from her young daughter’s swimming lesson finds that the nanny who was caring for her six and two year old has murdered them both and left their bodies in the bathtub. It is this story that inspired Slimani to write The Perfect Nanny.

If you have already read Adele by the same author, you will know by now that Slimani writes damaged women very, very well. Louise, the nanny in question, is a different kind of broken to Adele but shares the same mix of victim and aggressor. She has led a hard, undistinguished life and now, in middle age, finds herself riddled with seemingly inescapable debt. From the very get go, you know the children are, respectively, dead and dying and yet the book loses nothing by giving this away. The question is, how did she end up murdering her charges, when to all concerned she seemed like the eponymous, perfect nanny.

If you have young children and you ever intend to avail yourself of the services of so much as a babysitter, then this isn’t the book for you, but for the rest of us, it’s unmissable. I’ll never look at a nanny in quite the same way again.