The power behind the Grand National - the world's greatest steeplechase - for almost half a century, Mirabel Dorothy Topham's story has never been told. It is also the story of a marriage between a showgirl and a stage door johnny, a feckless and sometimes unreliable man. Mirabel had a dominant nature, was an astute businesswoman, tough as any man in negotiations but could be charming, kind and very humorous. It was a fortunate day for Arthur Ronald Topham when he married the beautiful actress - not only for himself but for the future of the Grand National.