Paul Pennyfeather
Paul is the protagonist of the novel and his educational career trajectory is based loosely on the author's. He is a gentle, harmless and modest young man who is studying theology at the fictional Scone College, part of Oxford University. He is not particularly drawn to either the subject or the college but is getting a degree as a condition of keeping his inheritance.
Unworldly Paul gets involved with a heavy drinking club and cannot hold his alcohol. Consequently he gets drunk frequently and does some ill-advised things. One of these, running through campus with no pants on, is the final nail in his Oxfordian coffin and he is expelled.
Having lost his inheritance he is forced to make some quick life decisions, one of which is becoming a teacher at a school nobody has really heard of, in a place that is really the middle of nowhere. He starts tutoring one boy in particular so that he can get closer to his mother, which works out as he plans, and they become engaged. At the time he is unaware that she runs brothels in South America and he cannot possibly forsee that he will be the one who takes the blame for this down the road. He is convicted of trafficking and prostitution and sent to prison.
After faking his own death, Paul is able to go back to the start of his adult life and start again. He almost receives the gift of a rewind, in that he is able to identify college as the place where everything started to go wrong, and he is now able to go back and do things differently in order to correct it.
Margot Beste-Chetwynde
The striking and beautiful society lady for whom Paul falls is rather more interesting under her veneer of propriety than she is on top. Appearing to be a well-off, stiff upper lip kind of English woman, she is running a string of South American brothels and is rather short on moral fiber. She is also involved in the trafficking of young women from the countries of the Empire to her brothels, which make her a great deal of money.
Although she lets Paul take the blame for the prostitution enterprise, she does feel a modicum of guilt about it and helps her new husband devise a plan for him to fake his own death and start again.
Dr Fagan
Fagan runs a school in Wales and is somewhat of a lifesaver for Paul after his expulsion from Oxford, offering him a tenure as a teacher, and unwittingly introducing him to Margot. He is a well-meaning man whose school is nondescript and although private, not really a blip on the educational radar of the intellectual classes.
