In the current 2003 guidance, the Department for Education and Skills advises schools to ensure that all relevant evidence is considered and the pupil's version of events is heard before deciding to exclude. The proper basis for a decision should be the civil test of the "balance of probabilities".
This advice was contradicted by a court last year, which held that where the pupil's offence involved allegations of criminal actions, the basis for any decision should be the more rigorous proof "beyond reasonable doubt".
If the only evidence available is from pupil eye-witnesses, their evidence must be presented to the parents of the child under threat of exclusion.
The pupils themselves might then have to face interrogation from the parents. Many heads feared that this could lead to intimidation of these pupils.
The Government has responded that where the allegations involve criminal activity, schools must be much more certain of the basis for the exclusion.
Since most permanent exclusion cases involve some criminal activity, the potential for confusion remains.