Sir: I think it is very unfair for Diana Appleyard to try and excuse her children's behaviour on a sort of legacy of "authorised libertarianism" as advocated by Penelope Leach. When my now 22-year-old daughter developed the "terrible twos", Dr Leach's Babyhood came to the rescue and helped this most anxious young mother to deal with hideous tantrums effectively, consistently and firmly. The behaviour ceased, I repeated the advice with the next three children, and I am still using exactly the same method on the increasing number of four year olds who enter my reception class who seem never to have had any order in their lives at home. I never smacked them either, but I am proud that my children could be taken anywhere and would be pleasant to be with. Yes it took a bit of effort, but Penelope and I did it together!