Nanny has implemented the old "Orwellian" trick, first mooted in Orwell's book "1984", of controlling the language in order to control what people can think.
Nanny's chums in both the government and the National Union of Teachers are banning pupils from using sexist insults at school, they fear that derogatory words can reinforce behaviour that leads to domestic violence.
Words such as "slag" have now been deemed to be "unspeak", ie you cannot use them.
Now dear Nanny, please tell us how you intend to ensure that pupils never utter these words again?
Paid informers perchance?