Somerset primary school teacher Nigel Leat filmed abuse
10 June 2011 Last updated at 18:35 BST
For years, a primary school teacher filmed himself sexually abusing children in his classroom while other pupils carried on with their schoolwork, oblivious.
Details of the crimes were heard at Bristol Crown Court.
The teacher, Nigel Leat, has admitted 36 sexual offences against against five girls.
John Kay reports.