Even by her own high standards, Meryl Streep is blindingly good as the British Prime Minister whose name became synonymous with brutally pragmatic market-driven monetarism.
Little wonder: in her fluent Polish in Sophie's Choice; her brittle English refinement in Fred Schepisi's Plenty; her flawless Lindy Chamberlain in Evil Angels; in a host of roles she has accustomed us to performances that blend precise artifice with astonishing dramatic conviction.
When she first appears here - incipiently senile and unrecognised at the corner store - we are amazed at the makeup artists' skills with latex and teeth. But when she speaks, she takes your breath away.
Within minutes she has inhabited the character so completely that she is more real than the real thing. It is an astonishing performance in a career full of them.
The problem is that it's in the service of a very ordinary film. Director Lloyd, a theatre veteran who helmed the film of Mamma Mia, and writer Abi Morgan (the dull adaptation of Monica Ali's Brick Lane), adopt a scenes-from-the-life approach that touches all the bases but lacks a beating heart.
The film is constructed as a series of flashbacks as the ageing Thatcher sorts through the possessions of her late husband Denis (Broadbent, marvellous), who materialises without warning to reminisce with her.
Each object she picks up sparks a memory and her life is reconstructed as a series of vignettes that take in her teenage years working in her father's Lincolnshire grocery to the day she leaves Downing St.
Those who are not fans of her politics will surely gag at what is a remorselessly sentimentalising approach (one which, incidentally, Thatcher herself would surely find nauseating) but that's only an incidental objection.
The flashbacks are intended to lend gravitas, but they lend ponderousness instead: every line is heavily laden so that even the good ones ("[Politics] used to be about doing something; now it's about being something") seem without lightness or wit.
It's a didactic approach that cries out for chapter headings: Sexism in the Commons; The Makeover; The Poll Tax. Despite Streep's remarkable work, we never get the sense of a flesh-and-blood person, something The King's Speech achieved effortlessly.
And technically it's too busy. The editing is head-spinning and some dizzying crane shots - notably the arrival at No 10 - are affected and distracting, the work of a musical theatre director who doesn't know when enough's enough. The montage of archival footage is skilfully cut in, although old TV pictures are painfully distorted in widescreen, but in the end it's a film that is too busy trying to rehabilitate Thatcher to let us ever see her.
Movie: The Iron Lady
Stars: 3 / 5
Cast: Meryl Streep, Jim Broadbent, Alexandra Roach
Director: Phyllida Lloyd
Running time: 105 mins Rating: M
Verdict: Meryl's choice - again