Herbert Nigel Gresley's first Pacifics, though notable in their day, were made universally famous by one of their number - 4722 Flying Scotsman. Throughout her life she has been feted and glamorised far more than any of her sisters and yet when appearing from the LNER Works at Doncaster in 1923 she was just another member of the class, but at some stage, early in her career, she acquired star status and to this day has not lost it. But why is this so and why do people care so deeply about this locomotive even though her deeds were easily exceeded by Gresley's A4 Pacifics? Was it her styling, her name, her performance or simply the work of very talented purveyors of slick PR? Or was it an amalgam of all these issues? As Flying Scotsman reaches 100 'not out' it is fascinating to reflect on these questions. But to do so we must consider how the Class came about, how they were developed, the impact they made on society as it was then, how they were sold to a waiting public and much more. From all this we may be able to understand why 4472 rose above the others and became an icon that still graces our lives today. It is, the author believes, a story without parallel in railway history.