A mother lets her children - aged just nine and six - swear all the time at home because she insists "language shouldn't be censored".
Lucinda Hart, 47, even allows Rafi and her younger sister Aelfrida to tell her to "f*** off" in private.
The author, who is from Mullion, Cornwall, insists the language is "natural" and should be used in preference to euphemisms.
