The post office is not ten yards from the building that used to be his nation’s Parliament. It surprises Thomas that such a thing exists at all. A guard in postal uniform is positioned outside, billy club in hand. Thomas is worried he will ask for some sort of identification papers, but all he requires of those who present themselves to him is proof of their solvency. Thomas holds up his palmful of coppers and goes inside.

Beyond the door there lies a little pocket of another world. The floors here are made from polished marble, the ceiling recently painted if no longer clean. Gentlemen in well-cut suits are reading newspapers or are queuing to see the postal clerk. Two ladies stand in hushed conversation, their expensive dresses as of yet unmarked by Soot; both wear veils to hide their faces and have footmen in attendance, their liveries hidden under bulky coats. A few dirty messenger boys scurry around but are careful not to address their betters. It’s like Thomas has stepped through a barn door and found a ballroom inside. For a moment he stands dead in his tracks, unsure what to do. Then he shrugs and joins the queue.

It is four deep and well-behaved. It startles him, this good behaviour, like silence after a protracted shout. Nobody grumbles, pushes, swears. They are like an unknown breed, peaceful, inoffensive: people who do not smell. Each shut up within his own intention, isolated and pure. Thomas stands amongst them and feels a pang of longing for this world of manners, the parlour-room peace of Discipline, predictable and without life. Just then a gloved hand touches his shoulder, firmly if without violence. It’s the doorman who has trailed him inside.

“Trade goes over there,” he says, turning the touch into a push, and moving Thomas towards a different clerk, in a separate cubbyhole, hidden far away to one side. Some workmen are queuing there, or rather are jostling, laughing, trading jokes.

Thomas moves over, listens to the men ahead and watches the gentry in their line, the well-drilled silence of the respectable. How many of them are in London on business, braving the city to look after their factories; how many for a holiday in the murk of sin? There must exist a tribe of locals earning a good living by acting as tour guides to the city’s charms.

“Next,” barks the clerk behind the counter.

An urchin, no older than seven, jumps the queue and gets into a shoving match with the man at the front.

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