Blake’s London is a dismal place, populated by crying infants, poor chimney sweepers, violent soldiers, and brazen prostitutes. Here the prophetic voice of the Bard returns to decry the existence of such a place. Everywhere he sees “Marks of weakness, marks of woe.” Like and Amos or Jonah of old, the Bard calls London to repent of its wickedness, its oppression of the poor, and its cultivation of vice, or be destroyed.
"London" follows an ABAB rhyme scheme throughout its three stanzas with little deviation from iambic tetrameter. Only "Mind-forg'd manacles" and "How" and "Blasts" in lines 14-15 are irregularly stressed. "Mind-forg'd" is stressed to further its contrast from the preceding three lines, each of which begins "In every" to create a litany of cries throughout London. Lines 14 and 15 give irregular stress to the two words in order to further disturb the reader, leading up to the oxymoron of the "marriage hearse" in line 16.
The poet expresses his disdain for the urban sprawl of post-Industrial Revolution London in terms as harsh as his praise for nature and innocence are pleasant. A society of people so tightly packed into artificial structures breeds evil upon evil, culminating with the “Harlot’s curse” that harms both the young and the married. It is as if a system has been created specifically to destroy all that is good in humankind, a theme Blake takes up in his later works. The reader is warned off visiting or dwelling in London, and by implication urged to seek refuge from the world’s ills in a more rural setting.
Blake's critique is not aimed only at society or the system of the world, however. Only the third stanza directly addresses one group's oppression of another. Instead, much of the poem decries man's self-oppression. One reading of the poem suggests that the Harlot of the last stanza is in fact Nature herself, proclaimed a Harlot by a narrow-minded, patriarchal religious system. In this interpretation, Nature turns the marriage coach into a hearse for all marriage everywhere, because marriage is a limiting human institution that leads to the death of love rather than its fulfillment in natural impulses.