‘He did it years before William Donaldson did The Henry Root Letters,’ said my husband querulously, as though I had accused him on peak-time television of saying the opposite.

The ‘he’ in question was Humphry Berkeley, who as a Cambridge undergraduate just after the second world war pursued an elaborate hoax by assuming the identity of a fictional public school headmaster, Rochester Sneath, to write embarrassing letters to the famous, eliciting risible replies.