The King's Speech - And the Academy Award for best royal goes to...

If most actresses will do anything to get to the top, once they arrive that often all changes as they suddenly become picky. Not so Jessica Alba. How else do you explain her steamy scenes with a man more than twice her age, not to mention a jaw-dropping nude shower scene, in the sexy "Mex-ploitation" film, Machete? Not only does the camera linger longingly over Alba as she takes the shower, it also features her in bedroom scenes with an ex-con played by veteran actor Danny Trejo, 66. We are told the underwear she wore in the shower was digitally removed afterwards, but it's still surprising for an actress who has always sworn off screen nudity.

Oscar season is in sight and the forelock-tugging has begun in earnest. For some reason, whenever a new film featuring the British monarchy appears, audiences genuflect in front of it. Hard-bitten critics perform the equivalent of a curtsy. Bafta and US Academy members swoon.

Tom Hooper's The King's Speech is the latest feature that has made the film world bend its knee. Since its premiere in Toronto last month, where it won the Audience Award, the film has been greeted with the kind of flag-waving enthusiasm that used to be reserved for the Queen Mother's birthday or the latest Royal Wedding. When the film received its British premiere during the London Film Festival, normally discriminating newspapers rushed to put gushing reviews on their front pages.

This is hardly a new phenomenon. We've been this way before with Stephen Frears' The Queen (2006), Nicholas Hytner's The Madness of King George (1994) and – if we look a bit further back in time – with Anna Neagle's rapturously received pictures about Queen Victoria in the 1930s and Alexander Korda's The Private Life of Henry VIII (1933).

The King's Speech is a decent film. If you have a maiden aunt of squeamish disposition, be sure to take her. Colin Firth's King George VI may swear a little in between the stutters but she will find very little else to offend. The movie is very handsomely crafted and designed. We're taken back to a misty, late-1930s England, part Brideshead and part Hovis ad. Colours are desaturated. There is a lot of tweed and fur on display. This is a world of Bovril posters, wirelesses and beautifully varnished old gramophones. Interiors range from palaces to abbeys to drawing rooms. The supporting cast is full of redoubtable British character actors: Timothy Spall as Churchill, Derek Jacobi as the Archbishop of Canterbury, Michael Gambon as George V.

It is doubtless churlish to denigrate such a well-made movie. Firth excels as the stammering prince thrust on to the throne after the abdication of his brother Edward (Guy Pearce) during the Wallis Simpson scandal. With his quivering lips and severe frown, he is a winning mixture of decency, vulnerability and regal arrogance. Geoffrey Rush's speech therapist Lionel Logue is likewise a memorable creation: an eccentric who lives with his family in shabby gentility in a big hangar-like apartment. Logue is a failed actor without formal training as a therapist. He is a slightly seedy figure but he shares Bertie's determination and essential decency. Their many scenes together are the strongest element in the movie. Slowly, Logue goads and coaxes his reluctant patient into following his instructions. He uncovers the root of Bertie's stammer. (This largely lies in childhood trauma when his brother was beastly to him, his knees grew at odd angles and he wasn't allowed to use his left hand.)

As an uplifting yarn about a public figure overcoming a stutter and thereby achieving a new-found self-respect, the film works well enough. The script makes some trenchant points about class and status in 1930s England. Bertie, strangely given his background, is the underdog who comes through in the end. The dismaying side to The King's Speech, though, is its extraordinarily dewy-eyed view of monarchy and, in particular, its uncritical view of the King's role as father figure to the nation. When the monarch speaks, Britain grinds to a standstill. Men in pubs nurse their pints of beer and listen intently. The servants and the toffs alike are spellbound. The divide between classes is still huge – and no one seems to mind. In one excruciating scene, Bertie's wife (Helena Bonham Carter) turns up unexpectedly and Logue's wife belatedly realises there is royalty in her midst and plunges straightaway into an ecstasy of bowing, scraping and nodding.

Charles Laughton's Henry VIII was a king in very different register to Firth's hesitant Bertie. Nonetheless, way back in 1933, when The Private Life of Henry VIII opened at the Radio City Music Hall in New York, Laughton likewise had American audiences and critics prostrating themselves in front of him. Laughton's Tudor monarch was a bellowing, gluttonous bully. Watching him, it is hard not to think of Freud's phrase, "His Majesty the Baby". Whether it was his way of eating chicken or his rush to have his wives executed, he was intemperate in the extreme. The film was marketed in the US as "a super-colossal portrait of a forgiving soul, always ready to bury the hatchet – in the wife's neck".

Laughton's performance won him an Oscar and the film made its Hungarian producer/director Alexander Korda a fortune. Lajos Bíró's screenplay was nowhere near historically accurate – and it didn't pretend to be. It played up the roistering side of the King's personality. Its very title was considered risqué. However, it tallied closely with what US showmen felt that movies about the monarchy should be about. The costume design was sumptuous. There was plentiful footage of palace life and as much pomp and ceremony as you would expect. This was the first really successful British talkie in the US market – and movies about British kings and queens have followed in its wake ever since.

Anna Neagle's forays into playing royalty on screen were more restrained. In Victoria the Great (1937) and Sixty Glorious Years (1938), she played the Queen as if she was a glorified Blue Peter presenter – prim and practical. Herbert Wilcox, Neagle's husband and director, wasn't making bodice-ripping yarns about the Tudors but very respectful mini-hagiographies. It wasn't just in Britain that the films found an audience. Victoria the Great was shown to acclaim at the Venice Festival in the height of the Mussolini era. Audiences warmed to the cosiness of the films. As the historian Jeffrey Richards has noted, Neagle's Victoria was "a genteel, loving and middle-class monarch".

The lasting irony about "royal" movies is that they inevitably end up reinforcing the institution of monarchy, whatever the intention of the film-makers. Korda was keen to make money and (as an émigré) to underline his establishment credentials. Herbert Wilcox was keen to make money but also seems to have been sincere in his admiration for Queen Victoria. Virtuoso screenwriters such as Alan Bennett (The Madness of King George), Peter Morgan (The Queen) and Julian Fellowes (The Young Victoria) have a complex and nuanced view of the monarchy. Nonetheless, once the costumes have been designed, the palaces hired, and actors have been cast, the projects take on lives of their own. Any critique of royal behaviour and sense of entitlement is undermined by the sheer flag-waving pantomime of it all. Nigel Hawthorne's King George III may be as mad as a hatter and treated abominably by his physicians, but whatever indignities he endures, it doesn't threaten the mystique of majesty... at least as presented on the big screen.

Colin Firth excels in The King's Speech. Nonetheless, in the rush to crown him with awards, there is a risk that the real richness of his portrayal will be overlooked. In the early scenes of the film, Logue seems blithely unconcerned that he is in the presence of a potential king and treats him like any other patient. However, the more time he spends in Bertie's presence, the more deferential he becomes. By the final reel, he seems as awestruck by the King as any of the other courtiers who hang on his every word as he makes that memorable early wartime radio speech about the threat of Hitler. We have to pinch ourselves to remember that Firth is an actor giving a performance. If we're too deferential, we won't register fully just how subtle and moving that performance really is.

'The King's Speech' is released Friday 7 January 2011