Five years ago exec producer Robert Cooper and I sat in a BBC office in Wood Lane and pitched Margaret to the then head of drama commissioning, Gareth Neame. At the time, the idea of putting Margaret Thatcher at the centre of a drama - as opposed to a drama-doc or satire - was not something everyone warmed to as quickly as Gareth. She was - and still is - someone who divides opinion. Long-standing friends looked at us strangely.
For a writer, portraying a national icon is a daunting task. Real drama isn't about presenting a hero or villain but about finding the common humanity within a character. Rick Cottan saw immediately that Margaret should be a classic drama, a tragedy in the true Shakespearian sense that explores the things we all share - human frailty, loyalty, anger, hubris.
When the first day of filming arrived in July of last year, it came with an enormous sense of pride.Rick's perseverance and sheer genius paid off.
On set was our director, James Kent. In choosing a director you really have two possibilities - you can go with huge experience in your genre or you can follow your instinct. James is mainly known for his remarkable documentaries, but his passion, intelligence and clear vision for what the film could be had impressed us early on.
Each and every day when he wasn't filming or speaking quietly and calmly to Margaret Thatcher, Queen Elizabeth II or a member of Thatcher's cabinet, he was locked in focused and creative dialogue with Sanne Wohlenberg, our producer.
We had worked with Sanne before and been blown away by her exceptional ability to wring every last creative drop out of a budget. With Margaret she took on the challenge of a two-hour film spanning several time periods with umpteen, high-profile locations and a cast of 50 in a 26-day shoot.
In all the creative areas of design, lighting, costume, make-up, locations and casting there was a clear decision to put the dramatic challenges of the film above a slavish attempt to recreate and re-enact the ‘real' events or places.
A large part of the story takes place in Downing Street but even if we had been able to film there or to exactly recreate it in every dimension, we wouldn't have done so. What was important for us was a sense of epic scale. Scale has a psychological effect - it comments on Margaret's emotional state. It helps to understand the nature of power and being human amid the enormous scope and importance of her job.
Whether in a house in Bushey or the Middle Temple it was extraordinary to witness a cast and crew, most of who had lived under Thatcher's premiership, so totally committed to realising the emotional truth of Rick's script.
Production company: Great Meadow Productions
Director: James Kent
Executive producer: Kate Triggs and Robert Cooper for Great Meadow Productions and Bethan Jones for BBC Wales
Producer: Sanne Wohlenberg
Broadcast: Thursday 26 February, 9pm on BBC2
Project summary: Margaret is a compelling drama about power and betrayal. Starring Lindsay Duncan in the title role, it is a very human story about the private Margaret behind the public persona as she loses her grip on the power she has strived so hard to achieve.
Kate Triggs: My tricks of the trade
A mental note of all the exceptional things I saw in yesterday's rushes.
A bag of sweets to hand out when sugar levels are getting low.
An open mind but a clear idea of what everyone is trying to achieve.