Married to the elder daughter of 1st Earl Mountbatten, Brabourne was a survivor of the bombing which killed his father-in-law, mother and son.
Also, Lady Brabourne was related to the British royal family, and her aunt Louise Mountbatten was at that time the Crown Princess (later Queen) of Sweden.
In November the same year, Lady Brabourne's first cousin Philip, Duke of Edinburgh wed Princess Elizabeth, future Queen of the United Kingdom.
He graduated to the role of production manager by the early 1950s, and finally became a producer in his own right in 1958, with Harry Black a romantic story set in India, with war as the distant context.
John Brabourne received two Academy Award nominations for Best Picture, as producer of Romeo and Juliet (1968) and A Passage to India.
Having planned to murder Mountbatten, the Irish Republican Army (IRA) placed a bomb inside the boat on the night of the 26th.
Mountbatten and several members of the party were killed the next morning when the bomb was triggered by an IRA observer onshore who was armed with a radio detonator.