As a declared social reformer, Charles Dickens includes extravagant didacticism in his novel Great Expectations, and one of his main topics is social injustice. Having had a father who was sent to debtor's prison and having spent time there himself as the family was allowed to visit, Dickens grew to perceive Victorian society itself as a prison in which the poor were victimized by cruel laws and a partial justice system that incarcerated the poor and meted another justice to those of wealth and social class.
This theme of social injustice is played out with the characters of Mr. Jaggers and Magwitch. Mr. Jaggers, an unconscionable barrister who defends whoever has enough money to pay him and ignores others illustrates the maxim stated by famed defense attorney Johnnie Cochran who once declared, "The color of justice is green." These actions are illustrated in Chapter 20 after Pip has arrived in London and various persons charged with crimes approach Mr. Jaggers as he traverses the street to Pip; Jaggers addresses those who follow him. When two men ask him about their case, he tells them not to think because he does the thinking. Then, he asks them, "Have you paid Wemmick?" (his clerk) Those who have not paid him he peremptorily dismisses.
Much later in the novel, after Pip is visited by Magwitch, the convict so touched by Pip's kindness that he becomes the secret benefactor for Pip in his venture to become a gentleman. Pip learns the old convict's history, a story that captures the poignancy of the plight of the orphaned and poor as well as the egregious acts of injustice doled out by the Victorian courts. Magwitch relates to Pip his experiences of working for the gentleman Compeyson, and how he was exploited by him. When he first began committing petty crimes for Compeyson, Magwitch was punished sometimes when Compeyson was not:
"The time wi' Compeyson was a'most as hard a time as ever I had; that said, all's said. Did I tell you as I was tried, alone, for misdemeanour, while with Compeyson?"
After some time, Compeyson was finally tried along with Magwitch, but Compeyson demanded separate trials and received one. Magwitch sold whatever he could to afford Jaggers as his defense attorney. During the trial of Compeyson, his advocate constantly pointed in his defense of his client to Magwitch as the more culpable:
"'My lord and gentlemen, here you has afore you, side by side, two persons as your eyes can separate wide; one, the younger, well brought up, who will be spoke to as such; one, the elder, ill brought up, who will be spoke to as such; one, the younger, seldom if ever seen in these here transactions, and onl.... Can you doubt, if there is but one in it, which is the one, and, if there is two in it, which is much the worst one?' And such-like."
At the end of the trial, Compeyson, the gentleman who devised all the schemes but has witnesses who attest to his belonging to certain societies and his proper association with people of good name, is given a lesser sentence than poor Magwitch.
"And when the verdict come, warn't it Compeyson as was recommended to mercy on account of good character and bad company, and giving up all the information he could agen me, and warn't it me as got never a word but Guilty?"
Magwitch becomes symbolic of the poor, barred from hope in life by irons and chains, in despair of rising from his social realm with no prospect of justice by the prison of society which locks people in their class positions. As an example, when Magwitch is dying, Pip is informed that because his benefactor is a convict the Crown will claim all the money that Magwitch has intended for him.
Of course, the theme of social injustice is also illustrated with the unkindness of Estella toward Pip, whom she derogates as a "common laboring boy" as well as the haughtiness of the relatives of Miss Havisham, who display the ostracism of the poor by the rich as they disdainfully regard Pip in his reduced circumstances. But, after he comes into money, they act differently toward him. Then, too, Miss Havisham initially treats Pip as a mere training object on whom Estella can practice Miss Havisham's misandry.