It's not a title, it's an appellation.

William and I can separate life into two parts. There were those years when we were blessed with the physical presence beside us of both our mother and father.

And then there are the 10 years since our mother’s death. When she was alive, we completely took for granted her unrivaled love of life, laughter, fun and folly. She was our guardian, friend and protector.

She never once allowed her unfaltering love for us to go unspoken or undemonstrated.

She will always be remembered for her amazing public work. But behind the media glare, to us, just two loving children, she was quite simply the best mother in the world.

We would say that, wouldn’t we.

But we miss her. She kissed us last thing at night. Her beaming smile greeted us from school. She laughed hysterically and uncontrollably when sharing something silly she might have said or done that day. She encouraged us when we were nervous or unsure.

She — like our father — was determined to provide us with a stable and secure childhood.

To lose a parent so suddenly at such a young age, as others have experienced, is indescribably shocking and sad. It was an event which changed our lives forever, as it must have done for everyone who lost someone that night.

But what is far more important to us now, and into the future, is that we remember our mother as she would have wished to be remembered as she was: fun-loving, generous, down-to-earth, entirely genuine.

We both think of her every day.

We speak about her and laugh together at all the memories.

Put simply, she made us, and so many other people, happy. May this be the way that she is remembered.