19th century London was a period of growth for london, it went from a population of 1 million in 1800 to nearly 7 million by 1900.
London became the largest city in the world, and an economic capital, not just of the British empire, but of all europe.
Unfortunately the city was not equipped to deal with such expansion, and while the city could claim to be wealthy, a majority of its citizens were poor and malnourished.
The first railway would not open until 1836, and as such horses, and carriages were still the only modes of transport for getting around the city.
The first sewers were not built until after "the great stink" of 1858, at the current point raw sewerage is just dumped straight into the thames.
In 1829 the home secretary established the first metropolitan police force. Nicknamed, bobbies, or peelers (after robert peel).
So while there is currently a police force in london, it is still relatively new. The numbers of both bobbies, and police stations is not yet at the desired point, and as a rule the populace are still distrustful.
In short this was a hard time for many people, with poverty and unsanitary conditions rampant in the slums, which are only getting bigger and bigger.