Brash, bawdy and utterly beguiling, The Favourite is, much like its subjects, something of a deceptive confection. While it may play as a broad period farce, revelling in the ribald excesses of its 18th Century English setting, underneath the pomp and powdered wigs it makes scathing commentary about the devastating nature of power struggles that remains blisteringly relevant in this Brexit/Trump age.

With England being ruled by the infantile, ineffectual, permanently ailing Queen Anne (Olivia Colman), her closest confidante, Lady Sarah Marlborough (Rachel Weisz) expertly uses her influence to assume control of the palace and, by extension, the kingdom. When Sarah's charming young cousin Abigail (Emma Stone) arrives in search of work, however, she soon captures the Queen's attention and begins to usurp Sarah as favourite; something for which Sarah will not stand.

In its depiction of Queen Anne's court, The Favourite eschews tightly-corseted, austere notions of history to positively luxuriate in unfettered decadence. That is most immediately felt in Sandy Powell's exquisite costume design, where vivid colours and exaggerated lines speak both to period and character. Weisz's Sarah, for example, favours masculine trouser suits while conducting business and glorious gowns when wooing the court or its Queen, while Stone's Abigail finds her clothing becoming ever more voluminous as her status rises.

Elsewhere, Fiona Crombie's production design is equally as glorious; tapestries are deep and rich, food is in gleeful abundance, courtiers indulge in duck racing and naked fruit lobbing, the corridors ring with music, anachronistically modern dance and drunken laughter.

Yet director Yorgos Lanthimos and screenwriters Deborah David and Tony McNamara are more concerned with exploring the dark corners of the palace, where secrets and lies are traded like currency, and diplomacy and democracy are shaped for individual ends. In this they are aided by master cinematographer Robbie Ryan (I Daniel Blake, American Honey), who shoots on 35mm, uses both traditional and experimental framing and works magic in the shadows, where candle-light casts ominous glows and corridors take on hellish proportions. 'Favour is a breeze that shifts direction all the time,' warns opposition leader Harley (a brilliantly caustic, coiffured Nicholas Hoult) and, as influence ebbs and flows according to Anne's whims, it is the country at large that weathers the storm.

If that's a message that cuts close to the bone, the film's gender politics are also deliciously pertinent. The intense battle of wits between these women is fought entirely by intelligence and cunning, yet both Sarah and Abigail know how to use their veneer of respectability — and, when it suits, femininity and sexuality — as both sword and shield. Moments where they trade thinly veiled threats while shooting pigeons, or when Abigail disarms an aggressive Harley with crocodile tears, are knowingly observed. And only Queen Anne seems to be honest in her childlike responses; which, tellingly, leaves her open to being controlled like a puppet on a string.

As the woefully manipulated Anne, Olivia Colman puts in a commanding, wide-ranging, often heartbreaking performance, nailing the obvious comedy of the character but also the grief and heartache that informs her idiosyncrasies. A brief scene in which she quietly explains to Abigail that her 17 pet rabbits each represent a child lost to her is devastating in its simplicity, a moment of genuine pain and pathos amidst the pantomime.

Weisz and Stone are equally as stunning in their roles, expertly handling the fast-paced dialogue (which recalls the very best of the screwball comedies) and often-physical comedy but, crucially, never losing sight of the human instincts — love, security, survival — that fuel their outlandish behaviours. As such, the indelible final scene, in which an ailing but mentally lucid Queen Anne fills the screen, towering over a meek and kneeling Abigail, serves up a particularly devastating blow; with the balance of power remaining entirely unchanged, both Sarah and Abigail have lost themselves in an act of sheer folly.

Screening on Thurs 18, Fri 19 and Sun 21 Oct as part of the BFI London Film Festival. General release Tue 1 Jan.