Campbell was the Public Relations Officer to Mountbatten. It was unusual in those days to have a PRO. Anyway, he wrote a biography on Mountbatten's years in India as viceroy.
Nehru let Mountbatten remain as Viceroy after India's independence but Jinnah refused. Out of spite, Campbell-Johnson stole some doodles that Jinnah had made on a piece of paper with rockets and fireworks and the word 'viceroy'. It was implied that this proved how power-hungry Jinnah was. In those days, it was unusual to have a PRO. The vain Mountbatten would be an exception.