For Penguin children's cover design awards, this design was inspired on the symbolism in the story. The illustration led design makes the book cover stand out on the shelf whilst also having some symbolism in the story. The relationship of fear from William about Sammy, the dog, at the beginning of the story, turning into one of love where Sammy finds William in the cupboard in the house in London, mirrors the loving relationship between William and Mister Tom.