"Any discriminatory behaviour should be quickly picked up and the appropriate action taken."

Ya think?! Spend a day in an inner-city comprehensive and tell me that's the case.

Inevitably there will be racists working in the school system, and there is very little anyone can do about this. However, if someone joins a racist political party (which constitutes action, not just thought) they have made a clear and public statement about their bigotry, and must be fairly happy to defend it. Such people do not belong in positions of power over the vulnerable, in this case children.