I'm reading Valerie Pakenham's book shown above.
She references a letter sent by Joyce Cary, a district commissioner (and later a well-known novelist) in northern Nigeria in 1916. Comparing conditions in his district to those in southern Nigeria, he wrote his wife:
"Northern Nigeria is a paradise compared to those parts. And the people are gentlemen. Not that slaves aren't seized up here and men eaten, but it is done in a polite manner - not obtrusively."
What could I add to that?