The Iron Lady

"Watch out, looking back. Don't dig too deep—you don't know what you might find..."

—Denis Thatcher's ghost, talking to Margaret

The Iron Lady is a 2011 Biopic about Margaret Thatcher starring Meryl Streep in an Oscar-winning performance as the eponymous character. The film uses the framework of Thatcher's dementia to look back on the fragments of her life through her increasingly-feeble grip on reality and memory.

For the trope, see Iron Lady.

Tropes used in The Iron Lady include:

Cloudcuckoolander: In her old age, Thatcher is getting a bit loopy. Mostly manifested through Denis (who, we should recall, is in Maggie's head).
Did Not Do the Research: Grantham, which is featured for less than five minutes, does not look like a Coronation Street set, and is not populated with people speaking with thick northern accents.
Fake Memories: It's implied that what we're seeing is somewhat coloured through Maggie's rosy lenses.
Foreshadowing: In the scene where Denis proposes to Margaret, she exclaims, "I donʻt want to end life washing up a teacup!" Sheʻs doing exactly that in the movieʻs final scene.
Ghost Memory: Denis.
Imaginary Friend: In the present-day segments, Thatcher is accompanied by the delusory figure of her late husband. Jim Broadbent is clearly having the time of his life playing Denis.
Important Haircut: As part of Margaret's New Look.
Never Trust a Trailer: The fact that Thatcher even has dementia isn't even mentioned, despite being one of the film's most central themes.
Selective Memory: Maggie's are definitely slanted in her favor.
Straw Character: Numerous complaints that the film didn't do this to Thatcher. Though the film is not really complimentary (even supposedly seen through Thatcher's own rose-tinted goggles), the fact that it had the audacity to portray her as human rather than evil incarnate motivated by sheer hatred of everything good outraged her critics.
Unreliable Narrator: There are hints that the flashbacks are an example of this--the film (i.e. Thatcher) conveniently glosses over the negative aspects of her rule. And also, young Denis is a Hollywood heartthrob.
The Falklands War: Exactly what it says on the tin.