WHEN I was about 13, we were taking a geography lesson, looking at Africa south of the Sahara. After hearing about the various cultures, ever-changing national borders, and the diminishing powers of the various European empires, a girl piped up: “All Africans are stupid because they live in mud huts.”

No amount of persuasion could convince her that they didn’t need central heating in most parts of Africa because of the weather. Forty years on, and some people’s opinion remains just as blinkered.

Paul Dobson, Bishop Auckland.