What is a Post-Apocalyptic Regency?

Just what it sounds like.

A terrible plague consumed the world in the late 1790s. More than half the population died. In England, it took several years, but the government fell, desperate for food, people rioted, and civilization fell.

Small outcroppings of sanity came forth, where the strong survive and try to rebuild what they once had. But is it enough? England still has enemies, and with no one to defend her shores, what will become of the Empire?