Sarah may or may not be the imaginary friend of an unusually gifted little girl called Annie. She is a rather naughty time-traveller from the 25th century and creates nothing but trouble for Annie’s long-suffering brother, Jack. The reader knows that Sarah is “real” but Jack is unconvinced. This is quite a promising first novel, though I have to confess that, just like her brother, I found Annie irritating at times.

Sandra Glover’s alien is more glamorous and the way she integrates the fantasy element of her story into a moving realistic tale about fostering is very skilful. She writes plainly and well, and many children will enjoy this book.

Adele Geras