You belong to a generation that came to political consciousness under Margaret Thatcher. Did writing the screenplay for The Iron Lady feel in a way like exploring your own adolescence?
I spent most of the Seventies living in Newcastle-upon-Tyne and most of the Eighties living in Stoke-on-Trent. They're both places that suffered under her - so I felt the effects of her policies. And I think in 2011 you still feel the effects of her policies. So she very much shaped the political landscape for me. But I also think of her as a cultural icon, a satirical figure - I grew up watching Spitting Image in the Eighties.
The director, Phyllida Lloyd, has said this isn't a political film, but a Shakespearean one. Do you agree?
Writing a film is like giving birth to a baby and then giving it up for adoption. I think there's a vividness to Phyllida's work that has elevated the film and made it a real roller-coaster ride. But I do think it's quietly political. If you're dealing with a powerful leader, you're inevitably going to have a dialogue with her political past. It was always my intention to interrogate Thatcher's political life. Where I think Phyllida is right is that, fundamentally, the film is a study of power. It's also a portrayal of dementia. And I think it's about the loneliness of power.
Are you prepared for people to complain that the film isn't political enough?
I didn't realise I was meant to have this huge agenda when I started writing the script.
I just went in as a creative writer. There will be films made about her that are far more political than this one, but this is a very small film about the aftermath of power.
Is that why it is told in flashback, from the point of view of an elderly Thatcher?
Yes. I was struck by the aftermath of Bill Clinton's presidency and also by watching Tony Blair leave office and go on the lecture circuit. What was interesting to me about Thatcher was that she sort of just stayed prime minister.
She wrote her memoirs, but she didn't, as far as I can see, have that huge lecture tour circuit. So she was very much preserved in the public psyche as the prime minister.
I saw it as a small film about what it's like to go out and buy a pint of milk and no one notices you. What's interesting about the opening sequence of the film when we see Thatcher, played by Meryl Streep, doing just that, was that Meryl did it in one take and no one recognised her.
The film is organised around a small number of important relationships - notably the one between Thatcher and her husband, Denis.
It's played as a kind of King Lear for girls - in a way, Denis [played by Jim Broadbent] is her Fool. He's the ghost on her shoulder.
I was very inspired by the film adaptation of Jean-Dominique Bauby's The Diving Bell and the Butterfly, which is a sort of flip-book of random memories. I wanted to see this woman [Thatcher] navigate her way through the flip-book of her past. More than anything, the film is about the isolation of power. For a politician to be so driven by conviction, so strongly resist consensus, meant that she alienated herself from her own cabinet.
Was her isolation also a function of class? She had a very different background from most of her colleagues.
Someone who knew her well said he thought class was the bigger hurdle for her than her sex. I think there's some truth in that. One of the reasons she fell in love with America was that it is a meritocracy.
If this is indeed a Shakespearean tragedy, what was Thatcher's tragic flaw?
I think everybody should doubt. It was part of being a strong leader and the woman that everybody looked to that she didn't allow herself to doubt.Her success was also her failing - her drive and conviction; her inability to truly engage and allow herself to be part of a consensus.
The flashback sequences in the film are sown with intimations of her downfall.
There are references made in some biographies that there was a kind of fury or frenzy to her leadership towards the end. When you're in a position where your own cabinet has told you, "It's time to go," and you've stopped listening to that, the reality check has gone AWOL.
Interview by Jonathan Derbyshire
Abi Morgan's play "Lovesong" opens at the Lyric Hammersmith, London W6, on 11 January. Details: lyric.co.uk