William Blake's poem, "London," presents a stark and bleak image of England's capital city. Dark and oppressive, the city is both the stage and the mechanism of indoctrination, crushing the spirit of individuality.
One of Blake's most quoted phrases relates directly to this idea of indoctrination -- "The mind-forg'd manacles" -- and it is in this phrase that we find the key to the poem.
The city is a place where individuals despair or give away their individuality. For reasons of economics, politics and religion, the figures that populate this London cry out or sigh in ways that signify the loss of individuality and the victory of systemic indoctrination.
How the Chimney-sweepers cryEvery blackning Church appalls,And the hapless Soldiers sighRuns in blood down Palace walls
"In the modern city man has lost his real being, as he has already lost his gift of vision in the "fathomless and boundless" deep of his material nature" (Kazin).
London is a real story or not?
No. The poem is descriptive of a view of London but relies heavily on a figurative perspective.
While the poem may be an honest and therefore truthful representation of Blake's views of the city (and what it symbolizes), the poem is not a "true story" in the sense of being an accurate telling of actual events.