“London” is a sixteen-line poem composed of four stanzas of alternative rhyming short lines. Written in iambic pentameter, the poem is beautifully rhymed. It is written in the first person and reports the narrator's observations as he walks through the streets of London: signs of misery and weakness can be discerned on everyone's face, it seems. Every man's voice—even the cry of every infant, a child who hasn't even learnt to talk yet—conveys this sense of oppression.

Blake applies varied rhetorical devices, of which the most striking and significant is repetition. For example, the word “charted” is reiterated in line1 and line2 to emphasize the fact that the streets and river are owned by the wealthy upper class. “Mind-forged manacle” is a metaphor. Blake compares limitations with manacles. The expression that Blake hears “manacle” is synesthesia.

Blake focuses his attention on the condition of London, England, the capital not only of the country but also of “culture,” yet, as the four stanzas make abundantly clear, Blake does not share the opinion that this city sets a positive example. Each stanza of “London” points out ways in which the British monarchy and English laws cause human suffering. He turns his attack on the capital city, thus pointing out that the very heart of the English Empire is diseased and corrupt. By choosing syphilis as the symbol for all that is wrong with England, Blake is able to condemn institutions and emotions that are sacred to most people: love and marriage. He seems more antagonistic toward the civil and religious laws that sexually repress people than he does toward the husband who cheats on his wife by visiting a prostitute.