I was tempted to call this extraordinarily successful novel, or novella, a little gem, until I remembered it was the name of a lettuce. Perhaps instead I should follow Simon Brett who tells us that ‘small but perfectly formed’ books are known in critics’ shorthand as ‘limpid’. Undertow is certainly limpid, enabling the reader to see down through the deceptively clear water to the dangerous currents beneath. It also has a hard strong quality, suggesting that ‘gemlike’ would not be altogether the wrong word. At the same time it is moving as well as beautiful, which is usually beyond the power even of emeralds.

A few months ago, when confined to hospital for several weeks, I found myself judging novels by whether they made me feel better or worse. Undertow should be on every hospital trolley as well as on prominent bookshelves, for it has a convincingly cheerful ending, characters whose fate the reader really cares about, a compelling atmosphere of its own and a style that stirs without dictating the response.

The young hero, Tim, tells his poignant story in the first person, the ‘she’ of the opening passage being his attractive but somewhat opaque mother who liked ‘taming wild things’ in the happy days when she and Tim lived in the country before his father left them and sold up