Jason Knauf, former communications secretary to both the Duke and Duchess of Sussex and the Duke and Duchess of Cambridge, has quit as chief executive of the Royal Foundation after several years at the heart of a tumultuous royal period. The American-born former corporate affairs executive is relocating abroad as his partner has taken up a diplomatic posting overseas. Mr Knauf found himself at the centre of the Duchess of Sussex’s legal battle against the Mail on Sunday after it emerged that he had helped the Duchess when she was drafting a letter she sent to her father, Thomas Markle. He was also thrust to the heart of a recent bullying scandal after a leaked email revealed he had raised concerns about the Duchess’s behaviour. In an email complaint sent in October 2018 to Simon Case, then the Duke of Cambridge's private secretary, he said: “I am very concerned that the Duchess was able to bully two PAs out of the household in the past year. The treatment of X was totally unacceptable.” He added: “The Duchess seems intent on always having someone in her sights. She is bullying Y and seeking to undermine her confidence. We have had report after report from people who have witnessed unacceptable behaviour towards Y.” The claims resulted in a Buckingham Palace investigation, conducted by an external legal firm, in which any current and former staff with concerns about Meghan’s behaviour are encouraged to take part. The Duchess has denied bullying. Last month, as the Duchess’s legal battle against the Mail on Sunday continued, Mr Knauf wrote to the newspaper’s lawyers emphatically denying that he had any copyright claim over the letter she had sent to her estranged father, landing a final blow to the newspaper’s case. The letter, sent in April, a month after the Sussexes’s televised Oprah Winfrey interview, insisted he led “extensive efforts” to protect the Duchess’s privacy and reputation during her time as a working member of the Royal Family, appearing to cast doubt over her claim that was “unprotected” by Kensington Palace staff.