Parents and unions want procedures for banning criminals from the classroom to be reviewed after convicted teachers were allowed to return to school.
They are concerned by the apparent inconsistency and leniency of the conduct tribunals run by England's General Teaching Council. They also believe the Government is passing the council some severe cases of misconduct which should be handled by Charles Clarke, the Education Secretary.
Government guidance says the Secretary of State can place teachers on List 99, banning them from working with children, if they commit sexual offences, serious violence, or misconduct "which indicates a risk to others".
But at least seven teachers convicted of such offences in the past year have been judged instead by the GTC.
These include a teacher who bludgeoned his wife to death, one who indecently assaulted a colleague on a school trip, three who committed violent attacks and two who collected illegal guns. Only Mark Parnham, jailed for six years for manslaughter, received a lifetime ban. Three were given fixed-term suspensions of up to four years and three were allowed to continue teaching.
John Dunford, the Secondary Heads Association's general secretary, has joined the National Confederation of Parent Teachers Associations in calling for a review. He said: "I have been surprised at how lenient the punishments have been compared to those given by the General Medical Council."
The Department for Education and Skills denied that it passed cases to the GTC incorrectly. Carol Adams, GTC chief executive, defended the rigour of its tribunals.