Why does the first convict take blame for taking food in Great Expectations?

In Charles Dickens' "Great Expectations", it is not explicitly mentioned that the first convict, Abel Magwitch, takes blame for taking food. Magwitch reveals his true identity to Pip towards the end of the novel, and their complex relationship forms the core of the plot. There might be confusion related to another aspect of the work. Can you elaborate on which scene you have in mind and provide further context?