This is the story of a princess who could not reconcile her royal status with her bohemian tendencies, resulting in a split personality that she never managed to shake off.
We meet her at twenty-one, receiving the news that she can't marry the divorcée she loves without forfeiting her privileges, and pressure comes down from high places to stay in the job. She seems to realise that she will never find happiness (and never does), so she might as well compensate with some high living.
This becomes the theme of the film, aptly introduced with a throaty chorus of 'That Old Time Religion', and if the partying seems too giddy and hysterical, it is no more so than the real thing was.
Lucy Cohu is triumphant in the title-role, having to age twenty years in the course of the story, so perhaps we can forgive her for not carrying full conviction at the most youthful stage. Best of all is the way she captures the petulance and sheer wilful mischief of the princess, who turns out to be hard work indeed for those she chooses to favour. Intriguingly, just once, she slips into a Northern accent, with her pronunciation of the word 'subject', while the person who ought to be talking Yorkshire, anti-royal MP Willie Hamilton, is mistakenly cast as a Scot.
We're warned that some incidents are not historical. The rumour of a lesbian affair sounds made up, though she would have loved the shock-value. Any idea of Prince Philip giving helpful advice to her new husband Tony Armstrong-Jones is right out: some say she chose Tony because he was the opposite of Philip, who simply couldn't stand the man. And when Tony is showing her round London's backstreets for the first time, the pub-brawl (involving Margaret) takes the slumming agenda a bit further than is credible.
One historically accurate scene shows Margaret watching Tony on TV, announcing their forthcoming divorce in a solemn spirit of regret. But they missed their chance to follow-up with her significant riposte "Best acting I ever saw."
As this film was made with at least half an eye on America, there had to be some rather obvious signalling of who's who in the zoo, and this can threaten the quality of the dialogue. Her confidante would normally have broken the news of her lover's suicide by just saying "Robin's dead", without having to provide a surname. Also the timelining of the story with newsreel clips and pictures of the moon-landings is as contrived as it is unnecessary.
If the male characters tend to deliver a wooden performance, it may just have been lack of opportunity. The plot largely reflects the boredom of royal life, and Margaret's circle was notably short of masterful and commanding males anyway. There were certainly some wooden performances by those men who were pretending to play the piano, with their hands conveniently out of shot. Viewers are used to this cheap trick, but they do expect to see some realistic mimicking, with the arms moving in rhythm, somewhere near the right end of the keyboard, at least. Not this time around. A pity, because the piano was a big part of Margaret's life, and many of her happiest hours were spent strumming or singing or both. Indeed, her doomed lover Robin was a jazz-pianist by profession. If they couldn't find a piano-playing actress for the star-role, they could at least have found one or two proper musicians to make up numbers.
Like all treatments of Princess Margaret, this film tries to conjure a woman of mystery and fascination out of basically ordinary clay. It may convince the young, who don't remember her. To others, it's just an agreeable piece of period wallpaper.