The two poems are direct contrasts to one another. The irony is that both poets, William Blake and William Wordsworth, were key figures in the Romantic period and therefore shared the same sentiments about mankind's relationship with nature. The Romantics believed that man had neglected nature and favoured materialism. Simply stated, the essential idea was that mankind had to return to nature, celebrate its beauty and find sustenance and vigour therein.
It is clear from the poems that each poet, though sharing the same ideal, approached the subject differently. Their perspectives are in direct contrast. Blake composed "London" in 1792 and the poem expresses his cynicism and despair with regard to the effects of the Industrial Revolution.
The tone of his poem is brutally harsh and portrays negative images of urban life at the time. Blake sees only exhaustion, sadness and degradation. He depicts city dwellers as entrapped "manacled," not only by their own materialistic idealism, but also by the government. He expresses despair at the victimization of those employed by the state to fight for their country, the neglect by the Church, the abuse suffered by innocents and the moral decay brought about by Industrialization and the accompanying urbanization. No one escapes this degradation, not even newborn infants, who are born into an immoral and uncaring society.
Conversely, "Composed upon Westminster Bridge" which Wordsworth wrote in 1802, employs a completely different approach. The mood of the poem is celebratory and the tone is positive and appreciative. Wordsworth's poem exposes none of the cynicism that is so clearly evident in Blake's poem. The poem declares unequivocally the poet's love and admiration for the beauty he sees around him. The sight that he sees is "majestic" not dark and dreary. The morning is so beautiful and is open to nature. The air is smokeless. The poet praises the splendour of the morning and is so overwhelmed by its beauty that he cries out to God in praise and remarks that even "the very houses seem asleep." In the last line he intimates that the city has a mighty heart, lying still.
Wordsworth uses beautiful imagery (simile, metaphor and personification) to describe the city (London) whilst the imagery employed by Blake is dark and depressing. One could argue that each poet's perception was informed by the time of day the poet describes (Wordsworth's poem was clearly written as the result of his inspiration in the early hours of the morning, Blake's could be based on his views later in the day or night).
The purpose of each poem remains the same however, that mankind should celebrate that which is good and natural and turn from voraciousness, exploitation, greed and corruption.