Crocker Harris is a teacher who teaches Greek to the lower fifth form a good school. He is the incharge of the form and as such he alone knows about the result of the students of his form which are to be officially announced the next day.
From Taplow’s comments about Crocker Harris, we learn that he is a teacher who takes his teaching very seriously. We learn that even on the day when he is leaving the school for good, he has called a student for extra work because the said student has missed a day last week.
He is the one who doesn’t like to be flattered. He will judge a student only by his merit and not because of any prejudice. It is a tribute to his character that although students like Taplow do not like his severity yet, they love and respect him from the core of their hearts.