William Blake's poetry is based on a complex and idiosyncratic philosophical and religious system Blake himself invented. His book Songs of Innocence and of Experience consists of a sequence of illustrated poems in which both the pictorial and verbal elements combine to reveal aspects of this new personal religion. The work contains both a series of pastoral poems depicting Innocence, often in terms of children and the countryside in a positive, almost Edenic light, and a grimmer set of poems depicting Experience, the real world of England's great industrial cities, in which young chimney sweeps and orphans are abused and starve. In this section, Blake tries to reconcile divine justice and mercy with the existence of evil in the world.
"London" is a grim poem, showing how political, social, and religious institutions were part of the evil that oppressed even infants and created "mind-forg'd manacles" trapping people in misery, whether in childhood, marriage, or careers. The possibility of redemption and rediscovering innocence amidst this experience of evil is treated in other poems in this section.