to this in Chapter 42.

Compeyson and Magwitch had been accomplices in crime.  When they were caught and put on trial, though, Compeyson arranged to have a separate lawyer and a separate defense.

The reason for this is that he was going to blame all the crimes on Magwitch. So Compeyson gets a lighter sentence because he blames it all on Magwitch.  His lawyer points out that Compeyson is younger and from a better family than Magwitch.  He says this shows that Magwitch is the one who is really at fault and Compeyson just got in with the wrong crowd and shouldn't be punished as harshly.

They are similar in many ways. First, they both have a connection to Havisham. One, Magwitch, doesn't realize his connection through Estella. The other, Compeyson, left Havisham at the altar. He is the man that has caused her demise and hatred for men. Both are cons in one way shape or form. Both found ways out of prison early.

Compeyson is smarter than Magwitch and he knew how to use a court trial to his advantage. A citation that proves this is:

"At last, me and Compeyson was both committed for felony - on a charge of putting stolen notes in circulation - and there was no other charges behind. Compeyson says to me, 'Separate defenses, no communication.'"

Compeyson used his boarding school education to set Magwitch up. If you read chapter 42, or even just a summary about it, you will learn that Magwitch was willing to be the muscle of an operation, and Compeyson was the brains... of all kind of operations. He swindled, foreged and stole, and let Magwitch take the blame for all of it.

The two convicts hate each other, and they fight since one convict will not let the other escape. The one shouts, "Murder!" and the other calls out, "Guard! This way for the runaway convicts!" Surprisingly, the other convict calls to the soldiers.

After the soldiers disrupt the Christmas dinner at the Gargerys' cottage because they need the services of a blacksmith, Joe and Pip follow them in their search for the two escaped convicts. Suddenly, they hear a loud shout from the convicts, who are struggling with each other. The soldiers "run like deer" toward the sound. "Here are both men!" pants the sergeant. They are struggling at the bottom of a ditch. The soldier orders them, "Surrender you two! And confound you for two wild beasts! Come asunder!" (Ch.4)

The convicts are bleeding and panting with exhaustion. As he shakes hair from his fingers and wipes the blood from his face, Pip's convict tells the soldiers, "I took him! I give him up to you! Mind that!" But the soldier tells him that his holding the other will do him little good since he is "in the same plight." Pip's convict replies that he does not expect his actions to help him. "I don't want it to do me more good than it does now. I took him. He knows it. That's enough for me."(Ch.4) Then the soldiers handcuff the two convicts. The other convict can barely speak. "Take notice, guard—he tried to murder me," he manages to utter. (Ch.4)

The first convict, who informs the guards that the other man is a gentleman, insists that he could have murdered this man if he had wanted. "Murder him? When I could do worse and drag him back?" (Ch.4) Further, he explains that he could have escaped, but he did not when he learned that the other man was out on the marshes, too. "Let him make a tool of me afresh and again? . . . No, no, no." He says that even if he died in the ditch, he would have held on to the other man." The two convicts exchange more insults. It then becomes apparent that the better-spoken convict is terrified of Pip's convict.

The mystery surrounding this hatred is clarified later in Great Expectations, in chapter 42. After Pip goes to London to become a gentleman, he rooms with Herbert Pocket, a relative of Miss Havisham. Herbert tells Pip the history of Miss Havisham's having been betrayed on her wedding day. A certain gentleman named Compeyson wooed Miss Havisham and "got great sums of money" from her. He also convinced her to buy her brother out of a share in the brewery for a large sum. Herbert's father warned Miss Havisham against this man, but she ordered Matthew Pocket out of her house, instead.

Pip's benefactor, Abel Magwitch, the convict from the marsh who, as a boy was only a street urchin in London, was exploited by Compeyson. Magwitch informs Pip that the man with whom he was fighting in the marsh is this same Compeyson, his enemy. Magwitch was a tool of this man "who got [him] into such nets as made [him] his slave" (Ch. 42). When they went to trial with charges of felony against them, Compeyson, dressed as a gentleman, had a separate defense and was given a seven-year sentence while the wretched-looking Magwitch was handed down fourteen. After their fight in the marsh, Compeyson's punishment again was light, but Magwitch received a life sentence. Magwitch tells Pip he "didn't stop for life" and escaped again.

In the past, Magwitch and Compeyson had been partners in the thieving business. Compeyson had been planning to swindle Miss Havisham out of her money by marrying her and then leaving her (with her money). When they were both captured, they turned on each other, informing the police of the other’s criminal intentions. Though they had been imprisoned together on the prison ship, they let their hated of each other grow. When they escaped, instead of aiding each other, they fought in the ditch. This allowed the soldiers (accompanied by Joe and Pip) to come on them and re-arrest both of them. They kept this hatred going for years. When Magwitch returned to England as Provis, Compeyson tracked him down. It was he who informed the police of Magwitch’s return. Magwitch was arrested and imprisoned, where he died. Compeyson died as he and Magwitch fell off the ship. 

As a social reformer, Charles Dickens was very concerned with Victorian society as itself being a type of prison.  That is, one was condemned to one's social position in London's society. While pointing to the flaws in the social strata of Victorian England, Charles Dickens called less for a change in social class than he did in the education of his characters that wealth and social position are worthless unless someone is a good person. The case of Magwitch and Compeyson exemplifies the perspective of Dickens that society is a prison and that social class is meaningless without goodness.

In Chapter XLII, Magwitch relates to Pip the story of his life. He explains that he has always been poor, a gamin of the streets who survived by means of 

"[T]ramping, begging, thieving, working sometimes when I could...a bit of a poacher, a bit of a laborer, a bit of a wagoner, a bit of a haymaker, a bit of a hawker, a bit of most things that don't pay and lead to trouble."

Further, he tells Pip how, after being in and out of jail, he met Compeyson, a gentleman in appearance who is well-educated, at Epsom race track. Compeyson fed him and gave him money, so Matwitch went to work for him,

"He was a smooth one to talk and was a dab at the ways of gentlefolks.  He was good-looking, too."

Magwitch worked for Compeyson in swindling, forgery, passing stolen bank notes, and such. Compeyson, Magwitch observes, was "as cold as death, and he had the head of the Devil." Too clever for Magwitch, Compeyson used him for all his underhanded dealings.

Eventually, Compeyson and Magwitch were arrested for the crimes they had committed. When they were charged with the felony of passing stolen notes, Compeyson told Magwitch that they should have separate defences.  Then, when they went into court, Compeyson was dressed as a fine gentleman, clean-cut and proper; however, Magwitch appeared to be but "a common wretch."  Magwitch tells Pip that the prosecution slanted the culpability for the crime onto Magwitch when he was only following Compeyson's instructions.

...it was always me that had come for'ard, and could be swore to, how it was always me that the money had been paid to, how it was always me that had seemed to work the thing and get the profit."

When the prosecutor tells the jurors to look at them and see "one well brought up, one ill brought up," Magwitch knew he was condemned for his poverty more than his crimes. The judge handed him a sentence of twice the length of the instigator of the crimes.

Magwitch is clearly a victim of the injustice of the Industrial Age that placed children in factories or the street where crime abounded as well as the corruption of the Victorian courts that had one justice for the wealthy/upper class and another justice for the poor.  While Magwitch tried to merely survive, Compeyson, a gentleman who gambled away his money, sought ways to extort from the wealthy.  For, he was the suitor of Miss Havisham who left her bereft at the altar, having forged a plan with her half-brother Arthur to take Miss Havisham's fortune.

Clearly, Magwitch is a sympathetic figure, a man who could have been good if he had not been so poor. When he is able to help Pip become a gentleman, Magwitch vicariously lives through Pip, hoping to vindicate his miserable life through the successes of Pip.  On the other hand, Compeyson simply is a blackguard, a man of no virtue or ethics; he is totally devoid of any redeeming qualities.

In the Charles Dickens’ novel, “Great Expectations,” Magwitch is a convict who frightens the young boy, Pip, into providing him with food after he escapes the hulks (prison ship). Later, when Magwitch visits Pip in London in order to reveal the fact that he is Pip’s secret benefactor, he begins to relate the story which explains how he came to be imprisoned for crimes. According to Magwitch, he was born under desperate circumstances and his adult life demonstrated no improvement in the circumstances of his birth. Therefore, when Compeyson, a skilled and heartless villain draws him into an elaborate plot to defraud people of their money, Magwitch complies. Once they have been accused and scheduled to stand trial, Compeyson communicates to Magwitch that he wishes to have ‘Separate defences, no communication,’ Without the benefit of a skilled and knowledgeable lawyer and the misleading appearance of Compeyson, Magwitch is sentenced to fourteen years in prison, while Compeyson is only sentenced to seven years.

Magwitch is arrested as he is on his way back to New South Wales, with the help of Pip and Herbert Pocket. As he is being rowed out to the transport ship, Magwitch sees a covered figure on the other side of his captor. He uncovers the figure’s face and sees that it is Compeyson. He cries out and grabs Compeyson, tipping over the boat. As Pip and the others in the boat are taken aboard the galley, it is seen that the two convicts are gone. Soon, Magwitch is rescued, but Compeyson disappears. His body is later found. It is unclear whether Magwitch is directly responsible for Compeyson’s death, but he is most likely the reason he was taken underwater. He is thus at least indirectly responsible for Compeyson’s death.