More than 1,550 members of the National Association of Schoolmasters Union of Women Teachers have faced a police investigation since 1991. There were just 62 convictions.
Union statistics show that the number of allegations annually peaked at 191 in 1999. Just three resulted in a conviction and in 119 there was no further action after investigation.
In the first seven months of 2002, there were 97 allegations. Only one went to court. There was no conviction.
Bob Carstairs, assistant general secretary of the Secondary Heads Association, said: "None of our members have been accused of physical or sexual assault in the past five years. But among calls that members make to us, one that crops up almost daily is that a member is aware that a teacher has been accused of hitting a child and wants to know what procedures should be followed."