Two preconceptions about The Iron Lady, the long anticipated film about Margaret Thatcher’s life, are laid to rest on seeing it. The first was that it would be a hatchet job on our former prime minister. Not so: the film is relatively even-handed, and for long stretches sympathetic to its subject. The second was that it was a travesty for Meryl Streep, the American actress, to be playing such a very English character. Well, those doubts have been assuaged too; Streep is splendid, giving a detailed, authoritative performance that goes way beyond accurate impersonation to evoke Thatcher’s spirit. One can think of a few talented British actresses who might have acquitted themselves well in the role, but it’s hard to imagine them doing it better than Streep. Screenwriter Abi Morgan (TV’s The Hour) has fashioned a story rooted in the present, with Thatcher in her 80s, afflicted with memory loss, largely confined to her home and facing the task of clearing out the clothes of her husband Denis, who died eight years previously. This device allows personal belongings to trigger memories of her past life, which is recreated in flashback. Cue a gallop through a life forged by her passion for politics — starting in her teens in her father’s grocery store in Grantham, where she is splendidly portrayed by Alexandra Roach, and through to her election as Britain’s first woman PM. Events come and go in a blur — IRA attacks, the Falklands war, the Brighton bombing, the miners’ strike, the poll tax riots — before her leadership crumbles. These episodes are interrupted by continued returns to the present, as she shuffles around her bedroom. This is a double-edged script device. On one hand, to portray Thatcher for so much of the film in a state of dementia feels skewed. Yet these scenes are by far the most affecting. In this state, her late husband appears to her, and they talk. (Denis is played by Jim Broadbent in a reading not far removed from Private Eye’s Dear Bill column as a convivial, golfing yarn-spinner) His presence is a trick of a failing mind, of course, but only in these present-day passages can Streep play the Iron Lady with any vulnerability. For much of her tenure in No10, there’s less of a character to mine: she’s mostly an implacable, relentless force of nature who brushes resistance aside. How people react to The Iron Lady depends on their attitude to her. David Cameron and Nick Clegg may squirm at a line in which she mocks coalitions. Trade unionists will find it too kindly. It may not find favour in Argentina. (“Sink it!” she snarls about the Belgrano.) Yet US Republicans, currently lacking a presidential candidate with a fraction of Thatcher’s conviction and confidence, will surely drool over it. This is a brave stab at a contemporary life, and even with its flaws it does Margaret Thatcher a certain grudging justice. Awards should be coming Streep’s way; yet her brilliance rather overshadows the film itself.