I think that the title of the work might help to express the theme of universal brotherhood. The idea of all men and people living in a world devoid of boundaries and geographic constraints helps to convey the idea of universality in identity. Cultural and natural barriers to collective solidarity are diminished in the mere theme. The "air" that is everywhere is another element that conveys universal brotherhood, invoking President Kennedy's appeal in that "We all breathe the same air." Kirkup opens the poem with discrediting the military and nationalism that divides human beings from acknowledging one another. The notion of how basic physicality of appearance helps to bring people together is reflected in the poem, conveying the theme of universal brotherhood. The poem is a call to action in transforming the world into what it should be in terms of a realm where all human beings are able to identify with one another and not against one another. This is a declaration of a theme of universal brotherhood evident in the poem from the opening to the closing line and sentiment.