The first thing you have to get your head around is that Pablo Larrain's new film "Spencer" isn't 'about' Princess Diana, at least not in any literal sense, although Diana herself is never off the screen. Perhaps a title at the beginning, 'a fable based on a true tragedy', is the clue. This is a fantasy or maybe simply a tragedy, (of the Shakespearean variety), in which everything is filtered through the gaze and the mind of a mad Princess of Wales, (Hamlet and the Court at Elsinore as imagined, rather than actually seen, by Ophelia). Larrain and screenwriter Steven Knight's Diana may as well be a fictional character since nothing we see is 'real' even if some of it may be true.
It's set over the three days of Christmas at Sandringham, presumably after Charles and Diana have separated and Diana has returned for the holidays. In this version of events, that clearly never happened, she is already deeply disturbed, blaming the Royal Family and Charles' affair with Camilla for everything. The only affection she gets is from her two sons and her servants, particularly her dresser, (a superb Sally Hawkins). Her in-laws hover in the background like zombies ready to devour her and like zombies are mostly silent with only Charles and the Queen, (as well as William and Harry), given anything to say, (Charles tries to be sympathetic, the Queen doesn't). "The Crown" this isn't. Knight has no sympathy for any of them though it's never clear if he believes that they were responsible for Diana's supposed breakdown, Only dresser Maggie, (Hawkins), head chef Darren, (Sean Harris), and senior equerry Major Gregory. (a brilliant Timothy Spall), are prepared to indulge her and let her go her own way.
Of course, none of it is true. This could be any woman having a serious mental breakdown anywhere and at anytime and stylistically this is a tour-de-force built around a phenomenal performance by Kristin Stewart as Diana. Yes, she captures the mannerisms perfectly but is there any evidence that Diana was as off-the-rails as she's presented as being here and while the Royal Family are certainly as dysfunctional as any dysfunctional family could be, I've never for a moment believed they were ever this cold, (this is the chilliest Christmas of any screen Christmas I've seen), but this is not the point.
The fault lines governing relationships and the fragility of human behaviour is what has always interested Larrain and this film is no different. Despite streaks of humour this is far from comfortable viewing and it's unlikely it will prove popular at the box-office. Stewart's Oscar, however, is virtually guaranteed; this is as fine a piece of acting as I've ever seen and other Oscar contenders such as Jessica Chastain and Lady Gaga will have to resign themselves that 2021 just wasn't their year.