In his poem "Crossing the Frontier," A. D. Hope uses the eponymous frontier as a metaphor for social attitudes towards pre-marital sex. In the opening stanza of the poem, the two protagonists, a man and a woman, are stopped at this metaphorical frontier and told that "they (will) have to wait." At the frontier gate, this couple meet all of "their most formidable friends," who represent the arbiters of social morality. The line, "surely holding hands (is) not a crime" suggests that, to these arbiters, holding hands is indeed a crime. The act of holding hands here is an innocent sign of affection which euphemistically represents pre-marital sex.
In the second stanza, the woman in the couple meets her father, who "wear(s) his conscience like a crucifix." The implication here is that the father thinks he is a martyr for his morality. He thinks he is a martyr in that he bears the shame consequent of his daughter engaging in pre-marital sex. Also in the second stanza, the man in the couple meets his aunt, who looks at him in such a way as to express that he and his partner are "doing wrong" by engaging in pre-marital sex.
Also at the frontier, and described in the opening line of the third stanza, are the mothers of both the man and the woman. The two mothers are, metaphorically, "weeping floods," implying that they are upset and ashamed of their children for engaging in pre-marital sex. In the next five lines of stanza three, the poet lists all of the other figures who also meet, or rather confront, the couple at the frontier gate. All of these figures hold positions of authority and thus personify social morality in a broad sense. These people include a "head-mistress," "the parish priest," and "the bank manager."
In stanza four, the poet describes the implacable stillness of the scene at the frontier gate. The people seem like "they ha(ve) stood there ... for years," and "nobody stir(s)" or even "risk(s) a cough." This stillness represents the implacability and inflexibility of the social attitudes with which the couple are confronted. This stillness also emphasizes that the confrontation at the frontier gate is an impasse.
In stanza six, "the wedding march" is played over the "loudspeakers" at the frontier gate. After much contemplation, this seems to be the solution to the impasse that the moral arbiters at the gate come up with. The couple must get married so that they can legitimately engage in pre-marital sex.
In the seventh stanza, the man, who is behind the wheel of a car, holds the woman's hand and says, "We must turn back." The man is obviously upset. His voice breaks, his "senses reel," and his hand, "so tense in hers, go(es) slack." At this moment, the woman suddenly laughs and tells the man to "Get out! Change seats! Be quick!" The repetition of short, exclamatory sentences here suggests an urgency in the woman's tone of voice. The woman then moves across to the driver's seat.
In the final climactic stanza of the poem, the woman drives the car towards the frontier gate. As the car collides with the gate, there is "a harsh, / Dry crunch that shower(s) both (the man and the woman) with scraps and chips." In a comic, surreal twist, these "scraps and chips" seem to have come from the bodies of the moral arbiters at the gate. Beside the woman there is her father's "moustache ... twitching still round waxen lips," and "streaming down the glass" of the car's windscreen are the "Mother's tears."
The fact that these parts of the moral arbiters are described as "scraps and chips" implies that these arbiters are non-human and robotic, which in turn implies that their prescriptive, conservative attitudes towards pre-marital sex are also inhumane. In this climactic scene, the poet makes it clear that his sympathies lie with the couple rather than those who set themselves up as moral arbiters.