She was recording his every move. She began setting impossible deadlines and giving him endless menial and pointless tasks. Worksheets had to be redone and he'd find his work scribbled out.
David (not his real name) was a bullied teacher, one of a growing band of thousands who are picked on by their superiors in school. Their bosses cause them stress and, in the worst cases, drive them into illness, depression and sometimes early retirement.
Nigel de Gruchy, general secretary of the National Association of Schoolmasters/Union of Women Teachers, says bullying of teachers by colleagues has reached "epidemic" proportions. A union survey reveals teachers subjected to serious bullying - constant and destructive criticism, sarcasm and innuendo, public humiliation, intimidation and threats. Some form of legislation to combat the problem is needed, says Mr de Gruchy.
But haven't grown-up bullies always been around? Why should bullying suddenly have become such a problem? A number of respondents to the NAS/UWT questionnaire voiced these concerns. "Bullying has become the Nineties buzzword, used quite erroneously to describe any form of pressure put on a teacher by a line manager," says one. Bullying could soon be used simply as "a means of rationalising inadequacy and stress from other causes".
John Meredith, an NAS/UWT officer who worked on the survey, agrees that some inadequate or lazy teachers might use the new awareness of bullying as a shield. But, he says, the overwhelming response to the survey was "huge relief" that someone was listening to what was felt to be a genuine problem.
Certainly, many of the stories of bullying are disturbing. The recent increase, the report suggests, is largely the legacy of the Thatcher era, with its emphasis on competition and "macho management" styles.
"Schools have become businesses and teachers cost units," says Mr Meredith. "Heads have become managers, although they were not trained as such. They are under immense pressure to balance budgets and produce results. They, in turn, put pressure on those below."
In David's case, things got worse when he refused to report another teacher to the head for an alleged misdemeanour. His department head became abusive and aggressive, sometimes in front of other people. She began making personal remarks to other teachers, alleging that a former male teacher was his lover and threatening to have him sacked.
The last straw came when, knowing that his wife was pregnant with severe complications, she gave him an unusually heavy workload over the holidays and had him disciplined when he returned with it uncompleted.
But it's not just teachers in the firing line; headteachers get bullied, too, particularly by governors in the grant-maintained sector. Jenni Watson, national secretary of Redress, the bullied teachers' support network, has received dozens of calls from headteachers suffering harassment and interference from governors. "Bullying flourishes particularly well where the local authority is not there to intervene," she says.
The NAS/UWT survey found that adult bullies in schools are mainly male headteachers in their forties and their victims are mainly female teachers in their forties. But deputy heads and department or year heads are often guilty, and men can also be bullied by female colleagues.
David suffered two years of bullying from his female head of department before taking action. Last month, a governors' grievance panel upheld his complaints and demanded that he receive a written apology. It was a long, hard fight, involving Redress, the police, a solicitor, a union representative, a local counsellor, an MP, crates of written evidence and a pounds 1,000 overdraft.
"Admitting you are being bullied isn't pleasant," he says. "There's a danger people will think you're a wimp, have a persecution complex or can't cope. At first, you don't want to take it seriously. Then, at some stage, you realise it's not going to go away, that this person is out to destroy you."
Redress can be contacted on 01405 764432.
What to do if you find yourself under attack
Elaine Bennett, an adviser on bullying for the Industrial Society, says workplace bullies are getting away with more now because people can't afford to leave their jobs.
"In the past, we could always walk away," she says. "Now people have to stay and their treatment gets worse."
To counteract bullying, she advises:
fight back, don't become a victim;
let others get upset for you;
keep a diary of bullying;
only take action against the bully when you are sure you have enough to nail them.