The controversial discussions were a protracted series of meetings of the British Psychoanalytical Society which took place between October 1942 and February 1944 between the Viennese school and the supporters of Melanie Klein. They led to a tripartite division of training in the Society after the war with the three groups of Kleinians, Anna Freudians and the Middle (or later Independent) Group.
In these sessions the differences between classical Freudian analysis and newer Kleinian theory were argued with considerable vehemence. The Freudian side was principally represented by Anna Freud, who was resistant to the revisions of theory and method proposed by Klein as a result of her work as an analyst of young children.
The Klein Group included Susan Isaacs, Joan Riviere, Paula Heimann and Roger Money-Kyrle. The Anna Freud Group included Kate Friedlander, and Willie Hoffer. The "Middle Group", who tried to apply a moderating force included Ella Freeman Sharpe, James Strachey, Sylvia Payne, Donald Winnicott, William Gillespie, Marjorie Brierley, and later, Michael Balint.
The resolution finally achieved was political rather than theoretical, with a gentleman's agreement being reached according to which both sides undertook never to attempt a take-over of the Society. The agreement stands to this day, with Freudian and Kleinian approaches co-existing side-by-side within the institution and upheld in separate training divisions.
The discussions were thus foundational in defining the nature of psychoanalytic thought and practice in the UK.