Dickens links criminality with social class in Great Expectations through the characters of Compeyson and Magwitch. Compeyson is seen as more genteel and gets off easier.
Dickens strongly believed that the justice system in Victorian England was slanted toward the wealthy. His most condemning portrait of this is in the characters of Compeyson and Magwtich. Compeyson is a criminal by choice, Magwitch by necessity.
Magwitch explains to Pip that he had to fend for himself when he was young, and ended up living on the streets in a life of crime. We’ve seen this before, in Oliver Twist. Dickens revisits the theme from the beginning of his career here at the end. Magwitch is what might have happened to little Oliver.
“So fur as I could find, there warn't a soul that see young Abel Magwitch, with as little on him as in him, but wot caught fright at him, and either drove him off, or took him up. I was took up, took up, took up, to that extent that I reg'larly grow'd up took up.” (enotes etext p. 233).
It is this childhood that led Magwitch to a life of crime because people assumed he was a criminal, or would be a criminal. He caught no breaks. Magwitch comments that he wanted to work, but couldn’t find steady employment. This is how he came to be an associate of the conman Compeyon.
Compeyson is a career confidence man. He enjoys it, and he is very good at making people think he is a fine, upper-class gentleman. Compeyson arranges to have a separate defense from Magwitch so he can cut all ties with him. Compeyson looks sharp at the trial too, and his lawyer takes advantage of this by laying the blame on Magwitch.
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 only suspected; t'other, the elder, always seen in 'em and always wi' his guilt brought home. 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? (p. 236)
When looking at these two characters, it is clear that Magwitch is the sympathetic one. Compeyson betrays Arthur and jilts Miss Havisham, causing her mental collapse. Magwtich goes to Australia, makes a fortune, and sends it all back to Pip. He wants to prove to everyone that they were wrong about him by making Pip a gentleman.