‘Bare? Extra? What does it all mean?’ asked my husband, sounding like George Smiley in the middle of a particularly puzzling tangle of disinformation.

My husband had just been reading about the Harris Academy in Upper Norwood (south London), which has banned its pupils (or students as they all seem to have become) from using a list of words including coz, ain’t, like, innit, yeah (at the end of a sentence) and basically (at the beginning).