The Princess described her schooldays, most of which were spent in Kent, as some of the happiest of her life.
Diana was a pupil at West Heath School in Sevenoaks which was an exclusive girls boarding school at the time.
It's a place where she certainly left her mark - with the above piece of graffiti still visible in her old classroom more than a decade on.
We speak to her former history teacher in her first TV interview about the 'fun-loving, deeply sensitive girl' she remembers.
Derek Johnson has this report.