Maurice Richardson in "The Observer" of 11 November 1973 was positive in his review: "Now in their seventies, the Beresfords, that amateur detective couple of hers whom some of us found too sprightly for comfort, have acquired a Proustian complexity. A code message in an Edwardian children's book puts them on to the murder of a governess involved in a pre-1914 German spy case. Past and present go on interlocking impressively. Despite political naivety; this is a genuine tour de force with a star part for Hannibal, the Manchester Terrier."