Trevor Morris, for one. He is one of three people who have turned their backs on lucrative careers and chosen to retrain as teachers, featured on Radio 4's Monday programme "Could Do Better."
The 50-year-old Mr Morris, formerly chief executive of Britain's largest PR group, has got on pretty well with his pupils. But he has a surprising weakness for a man with his past. "I've never been very good at names," he says. "I used to dread Christmas parties." Now, he has no one to whisper the name or offer a helpful drink as he stands tongue-tied before his pupils.
He caused merry laughter in class one day when he showed an 18th-century cartoon and described it as "an old man leaning on his hoe". How was he to know that is gangsta rap for a whore?