Investigations into teachers who are accused of child abuse should be anonymous, a top teaching union has said.

The high number of false allegations have left a catalogue of nervous breakdowns, family break-ups and blighted careers, the National Association of Schoolmasters Union of Women Teachers warned on Friday.

The union revealed figures showing members had faced a total of 154 allegations of abuse so far this year.

Despite the figures less than three per cent of abuse investigations have led to criminal convictions in the past 12 years.

The union called for the identity of teachers to be kept secret until they are either convicted or acquitted in court.

Ministers have pledged to speed up the investigation process but warned teachers could not be treated as a special case.NASUWT general secretary Eamonn O'Kane said a false allegation can sometimes spell the end of a teacher's career.

"Many teachers facing malicious allegations cannot sustain family relationships, have nervous breakdowns and cannot return to the classroom when their ordeal is over," he said.

"Allegations of child abuse must be investigated thoroughly with those found guilty facing the consequences. Such people have no place in schools.

"Anonymity will not hinder a full and proper police investigation. It will not protect abusers. Anonymity will strengthen the crucial principle of innocent until proven guilty."