When Prince Harry recently spoke about his own mental health in the wake of his mother’s death, I wondered if the therapist and writer Julia Samuel had been a major influence on him, and therefore the nation. She was a close friend of Diana, Princess of Wales, and in 2013 she was asked to be godmother to Prince George.

When we meet for a coffee one sunny morning in a café in west London, she is too discreet to discuss the Prince’s decision to talk openly about his own grief, except in general terms to salute his courage.