Pam tells Fred that she gave the baby aspirin to make it sleep and he tells her he won't be around until late that night. Suddenly, he tells Pam to find a new boyfriend, and breaks up with her officially. She gets very angry and Fred suggests that Mike is the only man who hasn't slept with her. When she insists that the baby is Fred's, Fred asks her to prove it, and she storms off, leaving the pram behind. Len follows her.
Mike and Fred are left behind and consider what to do with the baby. Pete and Colin, then Barry, arrive. They look at the baby and note that it needs a diaper change. Barry then takes the pram and pushes it, singing a profane version of "Rock a Bye Baby." Barry then plays with the balloon attached to the pram, eventually bursting it. The men all make sexual jokes, and Pete and Barry push the pram around recklessly. Pete pulls its hair and Barry pinches it. The roughhousing escalates, with Pete punching it. They each take a turn hitting the baby.
Suddenly, Pete throws a stone to Fred, suggesting that he ought to stone the baby. "Might as well enjoy ourselves," Barry says, and they all start throwing the stones. Mike takes out some matches, lights them, and throws them in the pram. A bell begins ringing periodically, and when the baby is dead, the boys leave the stage. Pam comes back on and picks up the pram, pushing it offstage without looking into it.
Scene 7. Fred is in jail, and Pam has come to visit him. He complains to her that a group of housewives attacked him when he was being brought in to the jail. He blames Pam for ruining his life and bringing the baby to the park at night. He then lies and tells her that the men who killed the baby were strangers and that he tried to chase them off. Pam tries to strategize with Fred about how he might be able to appear innocent in court, and offers to say that she saw the men who killed the baby. "That'd make it worse," Fred says.
Fred says to Pam, "There's bloody gangs like that roamin' everywhere. The bloody police don't do their job," blaming it all on the police. Suddenly, they are interrupted by Len, who has brought Fred some cigarettes. Pam hugs Fred and leaves, weeping. When Pam has left, Len tells Fred that he saw what happened, and that he ought to have stopped the murder, but didn't.
Scene 8. In the living room, Harry is ironing, while Len sits on the couch. Mary comes in and tells Len not to wear his work clothes—he evidently has a new job. Then Pam comes in, drying her hair and carrying a portable radio, listening to pop music. She accuses Harry and Len of stealing her copy of Radio Times.
When Fred breaks up with Pam once and for all, she storms off the stage, leaving their baby behind in a climactic moment of neglect. She and Fred argue about whether the baby is his, and he shames her about her promiscuity, prompting her to leave the pram behind. Pam has proven herself to be an exceedingly irresponsible mother already, neglecting her baby when it cries and feeding it aspirin to keep it quiet. In this scene, she goes even further by leaving it alone in the park.
The violence that follows is even more disturbing, as the men in Fred's gang wander onto the stage and eventually end up killing the baby. They slowly begin toying with it, testing the limits of how they can play with the baby. Instead of treating the baby as a soft and fragile entity, they imagine that, because it is so young, it has no feelings. The treatment of the baby is violent and disturbing, completely detached from human empathy and how an audience is accustomed to thinking about childcare.
The escalation of the violence towards the baby is almost unthinkable, lending it a kind of symbolic quality, in spite of the play's insistent realism. To see a group of grown men roughhouse with and ultimately murder a baby is quite outside the realm of what a typical audience might expect from the action of a play; thus, the act becomes representative of a certain kind of brutality and unbridled cruelty. The baby comes to stand in for the more vulnerable members of the society, and the men become a symbol for the wild and uncontrollable crowd of society. In this sense, we see that the play is examining the limits of human cruelty by presenting a horrible act so unflinchingly.
In spite of the horrifying violence of the murder of Pam and Fred's child, the play continues rather casually, and the characters seem unbothered. When Pam goes to visit Fred in jail, she is completely on his side and unconcerned about the death of the baby. Even after he blames the baby's death on her, she suggests ways that she might be able to help him win his trial. Then, Len reveals that he saw what happened, but does not imply that he is going to speak up. The shocking event becomes all the more shocking because the characters treat it as just a casual incumbrance.
The fact that the characters are seemingly never fazed by the horrible events that occur in the play has a rather stultifying effect, creating a monotonous structure, in which horrible things happen over and over again. The audience becomes a barometer for the horrors of the play because the characters are so completely numb to it, and their numbness has an almost anesthetic effect; if the characters can kill a baby and still feel nothing, nothing else that happens could possibly be shocking.