It was a moment of pure, delicious schadenfreude: former Cabinet minister Clare Short stood helplessly in front of a class of rowdy 12-year-olds, begging them to listen to her.
"Please," she repeated, with increasing desperation. "Please be quiet.
Ms Short, who resigned last year as minister for overseas development, spent a week last September working as a teacher at Southfields community college in south London. Highlights of the experience were screened last week as a BBC documentary.
Ms Short's unsuccessful efforts to keep control of a class of unruly 12-year-olds were documented in unforgiving detail by the cameras. Ros Taylor, a leading psychologist and expert in confidence-building, believes that her struggles reflect problems familiar to many teachers.
"I see teachers all the time who fail to realise that you don't have to be nice in the classroom to show that you like the kids," she said. "You don't have to make them like you to show you care. You can just be firm."
Most leaders tend to vacillate between aggressive authoritarianism and limp, woolly liberalism. Ms Short started as a liberal and slipped into authoritarianism when panic set in. Her first mistake was to admit that she was new, and ask for the pupils' help.
"She was always saying 'please'," said Ms Taylor.
"But you don't do that when you're in a position of authority. You expect that what you say will be done.
"Children will push boundaries as far as they can. Our job is to set them, and to be very clear about what happens when they break them."
Ms Taylor says there is also a third way: an option that has never appealed to Ms Short. Teachers should immediately establish clear rules, such as the expectation of silence in the classroom. These rules should be repeated until they are observed. Only then will pupils be rewarded by reaching the more interesting parts of the lesson.
According to Ms Taylor, Ms Short's decision to name a chronically late pupil "star of the week" revealed a fatal mishandling of the reward system.
"She messed that up," she said. "You only get what you reward. So, if you reward lateness, all the other pupils will be late, too.
"You need to negotiate a path with the class, treating them as individuals who can deliver what you ask."
Ms Taylor said that establishing clear boundaries could be liberating.
"If you don't have to ask for silence all the time, you can get on with whatever you really want to do. It sets you free."