The headmistress , Sarah Balham ( Gemmell ) , loathes Anderson .
The headmistress , Sarah Balham ( Gemmell ) , clearly wants to get rid of him , but the National Union of Teachers does not allow her to fire him .
The headmistress , Sarah Balham ( Gemmell ) , loathes Anderson and clearly wants to get rid of him , but the National Union of Teachers does not allow her to fire him .