Answer :
Dickens uses a lot of really sharp irony in Oliver Twist to satirize the various institutions (the parish workhouse system, the justice system, the poor laws, etc.) that he thought were inhumane and unjust.
For example, at the start of Book II, Chapter Five, the narrator satirizes Mr. Bumble by sarcastically calling himself "a humble author" in comparison to "so mighty a personage as a beadle"