The scene in Harbour and Room apparently belongs to the realms of imagination. In contrast with the literally representational landscapes and still lifes that Nash produced up to this point in his career, the picture’s imagery is markedly dream-like. The Nash specialist Andrew Causey argued that the subject matter of Harbour and Room grew from Nash’s conscious ‘attempt to deepen the intellectual basis of his painting’. The American writer Conrad Aitken lived near the Nashes at Rye and became good friends with Nash in 1930, and Causey used the influence of Aitken and Jean Cocteau to justify a symbolic interpretation of Harbour and Room:

"For Nash, the reflection of the boats in the mirror in Harbour and Room is a representation of death; not of absolute death, but the strengthening resignation to sleep and the unconscious. […] In Harbour and Room the water represents death in the sense of the nightly resignation to sleep, dream, and the unconscious […]."

Nash once referred to surrealism as ‘that much-worried word’. When required to define it, he offered the explanation given by the movement’s founder André Breton. As Nash explained in an essay of 1936, ‘[Breton] has attempted to convey an idea of surrealism by suggesting that a statue in a street or some place where it would be normally found is just a statue, as it were, in its right mind; but a statue in a ditch or in the middle of a ploughed field is then an object in a state of surrealism […]. It has, in fact, the quality of a dream image, when things are so often incongruous and slightly frightening in their relation to time or place.’ Nash was closely involved with the organisation of the First International Exhibition of Surrealism, which was held in London in 1936; on that occasion Magritte called him the ‘Master of the Object’.