The Constables
From The Fifth City Wiki
"The Constables protect the rich, the powerful, and the Masters. But sometimes, too, they protect the wretched poor."
The Constables are what remains of London's police force. All but one of them (a woman who is now called the Last Constable) have merged with Mr Pages' Ministry of Public Decency, so their duties now include censorship as well as attempting to protect the citizenry.
The segment of the Constables that actually enforces the law is the Velocipede (aka Bicycle) Squad, led by the Knuckle-Scarred Inspector. These are literally police enforcers racing around on penny-farthings, which must make for a hilarious sight!
One notable fighter for the law is the Implacable Detective, who ran unsuccessfully for Mayor of London in 1895.
