This is one of a series of six ‘Raiders’ begun in about August 1940 for the Air Ministry. Nash saw these watercolours as a continuation of his earlier work on the theme of ‘the monster in the field’, which in earlier incarnations consisted of strange misshapen tree trunks. Nash hoped his ‘Raiders’ would be published as war propaganda. This was never done. Nevertheless, the interruption of the machine here implies something a lot more threatening than a Surrealist juxtaposition of unlikely objects.