Last Tuesday, during the final assembly of the year at my daughter's school, pupils said goodbye to a teacher who was being elbowed out. Miss T was famous for her feebleness at imparting knowledge; the new broom of a head had decided it would make more sense to give the job to someone who could teach instead.

Yet last Tuesday morning, as the goodbyes were being made, the girls climbed up on to their chairs and clapped and whooped. They loved Miss T. She was a dear, kind woman who had been at the school long before they were even born. Of all the many things that they held against their reforming head teacher, the sacking of Miss T was the most unforgivable.

The previous weekend, the head of the schools watchdog, Ofsted, was quoted in the papers arguing that a bad teacher was needed in every primary school. Predictably, all hell broke loose. But Zenna Atkins was quite right. We do need the odd bad teacher. More than that: we need the odd bad manager and bad worker too. Her point was that a dud teacher teaches children to respect the authority of the office, even when the incumbent doesn't merit any. This lesson, she rightly pointed out, comes in handy later in life. Dealing with idiots in authority is a skill needed in every workplace and is well learnt early.