I went to schools in two different parts of what could be called northwest London in the early sixties.
My own experience with monitors is sadly the same as Sarajanes’.
Most of them would happily shop their grandmothers and teachers when on the lookout for suitable candidates would discount those children seemingly governed by the code of omerta.
The scary headmistress in my first school, (and boy was she scary)often left monitors in charge of classes.
Not because she was scared of anarchy breaking out but because she liked to encourage a healthy spirit of tale-telling amongst the monitors.