Why Kate didn't fight for Harry...

In the third part of our exclusive serialisation, RUSSELL MYERS reveals how Catherine thought it inevitable that Prince Harry would quit royal life and that, after getting married, the Sussexes had an agenda. She had tried to be the voice of reason but could not stop the breakdown of William and Harry's relationship. In the wake of the Oprah interview, Catherine believed the Sussexes were not to be trusted

- 

WILLIAM and Catherine had added reason to be nervous about the Sussexes' departure. William was intensely saddened at his brother's decision to quit.

He and Harry had been drifting apart for years, but now he knew deep down that there would be no turning back. Fond memories of their childhood, from helping each other through the tragedy of their mother's death, to growing up in the public eye, were now tarnished by the division at the heart of the family.

As an "outsider", Catherine had witnessed the deterioration of William and Harry's relationship.

She had seen Harry and Meghan become ever more bitter at having to follow the rules of a hierarchical and hereditary monarchy, until they felt as if they could follow them no longer.

However, Catherine had less interest than her husband in trying to persuade Harry to stay in his current role. She believed William and Harry's fundamental differences as the "heir and the spare" had created the inevitability of Harry wanting more from his role than being a bit-part player.

You don't just get Africa

What had started as a loosely formulated launch pad for their ideas would, over time, have to become more structured.

This shift suited William's mindset. He believed that the Royal Family had to evolve in order to stay relevant.

The institution could not afford to repeat the same tried and trusted methods of members of the family backing causes or turning up to the odd charity event.

They had to be effecting change.

However, this resulted in conflict around a perceived landgrab.

For years William had shown an interest in the environment and conservation, especially across Africa, and was keen to follow in the footsteps of both his father and grandfather.