Identify the irony in act 4 of the government inspector

The Chief of Police explains to the Mayor why one of the constables is not currently present: "There was a brawl outside town yesterday and he went to restore order—and he came back plastered" (231). The way the actor delivers the line may have verbal irony, but at the very least, there is situational irony present. A constable is supposed to behave properly and enforce the law, not behave dissolutely and shirk his duties. This is yet another example of how the civil servants of the town are self-interested and inept.