Sir: In her article on Diana, Princess of Wales (27 September) Ann Treneman follows others in using the non-existent title of King Mother in relation to the Princess. I have even seen this invention in a book by a supposedly knowledgeable writer. I assume someone has misinterpreted the title of the present Queen Mother.
A queen mother is a widowed queen whose offspring, male or female, is the current sovereign. Diana, following precedents here and abroad, could be styled Princess Mother, but she could never be Queen Mother without first being a queen.