Few things are more frustrating than for an exclusion to be overturned; and the aftermath can be damaging to a school. One reason why exclusions are overturned is ignorance of the standard of proof required. This is understandable with parents; it is inexcusable in other participants in the process.
The duty to ensure that the correct standard is applied belongs initially with the headteacher; but clerks and chairs of governors have the fundamental responsibility to ensure that they can explain the standard to others involved.
What is the standard? It is not the criminal standard (developed to protect liberty): no reasonable doubt of the individual's guilt. Regulations lay down that it is the lower civil standard, "the balance of probabilities", which applies where the only things at stake are money or reputation.
It does not mean 100 per cent certainty, but it is not necessarily 51:49 per cent either. This bare balance may apply for persistent defiance of authority, for instance. However, the law assumes it is inherently improbable that people will do outrageous things and so damage their reputation. So, if a pupil is accused of something criminal - assault, sexual molestation, extortion, theft - the case against him or her should be, in the simplest legal formulation, "distinctly more probable than not". Working to that standard and referring to it in hearings should enable heads to make the right decision and sustain it through the appeals process.
Two challenges to the regulations are being made on human rights grounds. However, under the Human Rights Act the courts cannot declare legislation void and this standard will continue to apply until Parliament changes it.
Richard Bird, Legal consultant to the Association of School and College Leaders.