I was extremely conscious of the compromises and choices that must be made whenever history is brought to the screen.

Book and historical adaptations are hugely popular on the Big and Small screens and when the producers looked for a screenwriter for Churchill, London‐based  screenwriter  and  historian Alex von Tunzelmann was the ideal candidate to tackle the subject matter.

Churchill follows Britain’s iconic Prime Minister Winston Churchill (Brian Cox) in the days before the infamous  D‐Day landings in  June 1944.

As allied  forces stand on  the south coast of Britain, poised  to invade  Nazi‐occupied  Europe,  they  await  Churchill’s  decision  on  whether  the  invasion  will  actually  move  ahead.

Fearful of repeating his mistakes from World War I on the beaches of Gallipoli, exhausted by years of  war,  plagued  by  depression and  obsessed with  fulfilling  historical greatness,  Churchill is also  faced  with  constant  criticism  from  his  political  opponents;  General  Eisenhower  and  Field  Marshal  Montgomery.

Only the unflinching support of Churchill’s brilliant, unflappable wife Clementine (Miranda  Richardsoncan) halt the Prime  Minister’s physical and mental collapse and help lead him to greatness.

Churchill is  directed  by  Jonathan  Teplitzky  (The  Railway  Man,  Marcella)  from  an  original  screenplay  by  British  historian  Alex  von  Tunzelmann  (Medici:  Masters  of  Florence)  in  her  feature  debut.

How does a historian become a screenwriter? It was a natural evolution and a deep fondness for films for von Tunzelmann. Writing for The Guardian’s “Reel History” where she analyzed the accuracy of historical movies helped guide her in the direction of screenwriting.

I was commissioned to write this in 2013. I’ve really had a long interest in Churchill and that period. I’d been thinking about writing about it for ages, but my inclination as a historian was to consider a biography, which would have been a very different angle. But when the producer approached me to write a screenplay about Churchill, I knew it was a fantastic opportunity. They had stumbled across this story about him initially being opposed to D-Day, which was a good jumping off point and allowed me to explore some of the things that were interesting about his character.

We are very familiar with Churchill as the great hero of 1940, and that’s the popular image of him in the U.K. The movie is set in 1944, which is a very different period—the war has been going on for years—and it is a really different Churchill. That’s also when Lord Moran, his doctor, started dating the beginning of Churchill’s decline. There is an incredible kind of poignancy. Just when the Allies were really beginning to win the war—D-Day was going to turn the tide on the Western front—that Churchill himself personally was beginning to lose, fail, and have difficulties. That seemed to say something about the incredible toll war takes on you, even if you are fighting as a politician, not as a combatant.

I was extremely conscious of the compromises and choices that must be made whenever history is brought to the screen. I wanted to focus specifically on [the] profound concern Churchill had for the men he would send to war; how a leader deals with that responsibility and guilt, especially when in the past it has gone badly wrong.

Film and television adaptations on the life and work of Winston Churchill are not scarce. However, given the extensiveness of his contributions, it seems both difficult and simple to choose an area to focus on during his lifetime. Alex dug deep into the man behind the public persona to reveal the lesser-known side; the Great Prime Minister who remained utterly focused on his duty while coping with extreme doubt and severe depressive episodes at a moment when the fate of the world depended on him.

My priority was to get to the character of a man who acknowledged his lifelong struggle with depression and yet who could inspire a nation; who lived with the guilt of his failures and yet could push through that to victory. He [Churchill] wrote beautifully about his depression. He referred to it as the ‘Black Dog.’ There were days where he couldn’t get out of bed, and yet he achieved so much. I thought this might be inspiring to people struggling with [similar] issues.

I based the narrative largely on the incredibly candid war diaries of Alan Brooke, a senior officer in the British Army played in the film by Danny Webb. They really kind of paint a picture of a man whose powers were beginning to wane, who was becoming more vague and couldn’t get out of bed in the morning,” she says. “And I found that a sort of extraordinary idea, that just at the point where the Allies were beginning to win the war, that Churchill himself — maybe partly because of the huge, kind of physical effort he’d put in — was beginning to fail. Of course, he is often with his trademark cigar in “Churchill,” but also with a glass.

The film takes place as Churchill wrestles with his own demons and fears on the eve of D-Day, a pivotal Allied campaign he initially opposed that would prove to be the turning point of World War II. Also, given more attention than in most other films regarding the Prime Minister’s work, is his marriage to Clementine “Clemmie”

The film does explore the strains that Churchill put on his marriage, and Clemmie, as in real life, is no silent ‘angel in the house,’ but a woman of remarkable character, holding strong opinions which were quite independent of her husband’s.

The journey from ideas and research to completed shooting draft was no quick path. Von Tunzelmann began writing the script in 2013.

My apartment was covered in index cards written in different colored Sharpees all across the room. Over time as I reached completion of the script, the index cards slowly disappeared and my apartment returned to normal. I worked in the library a regular day nine-to-five, but I did slip from that sometimes waking at three a.m. with the answer and needing to write that down.

Understandably there was to be a level of artistic or dramatic license taken to convey those emotions. Were Churchill’s doubts about the Normandy invasion as severe as depicted?

I think they were pretty serious. On the night before the invasion, when the ships had sailed, Churchill famously said to Clementine, “Do you realize that by the time we wake up, 20,000 young men may be dead?” For him, that was the worry. It did recall the 1915 Gallipoli campaign and the amphibious landings in the Dardanelles. I think it’s so extraordinary—how he responded to the Gallipoli disaster by leaving political life and actually going and signing up for the army and fighting on the Western Front. I think that is an amazing response that you wouldn’t see any politician doing today!

What were the most challenging aspects of the process for you?

The difficulty is the kind of four-dimensional game of chess that you’re trying to play. I was concerned with trying to be as accurate as we could be given that we were making a film for entertainment. I knew the essence of the story I wanted to tell and wanted it to be true to the sources that I found poignant—like Alanbrooke’s diaries at the time and some of Churchill’s secretaries’ memoirs—which made really excellent reading. And some of his own writing about his depression, which I found extremely poignant. I knew that those were the kind of aspects that I wanted to bring out. You know you’ll have to make certain compromises because real life doesn’t squish into three acts in a lovely, beautiful way. You know it is about determining what you think is really important, and then making the changes you have to make, with respect hopefully, for the truth of it.

But I did want to be true to that and I did care about respecting Churchill. Particularly this massively huge thing of portraying his depression, or at least giving a glimpse into that. We were very respectful about that because you can’t accurately diagnose a historical figure. It’s not possible to do because you can’t meet him or psychoanalyze him. All you’re going on is the clues in his writing, so I didn’t want to disrespect any aspect of that. But I also wanted to make that sympathetic, and I hope moving, because that is something to me that has huge resonance. Obviously most of us haven’t had to fight World War II, but a lot of us have experience with depression personally, or through a family member or friend, so I think that is an incredible thing. And I know some people may find that disrespectful—there is unfortunately still prejudice out there about how depression works—and they see that as making Churchill less of a hero, but in my mind, it makes him much more of a hero. I hope people find that inspiring.

If you would like to catch up on von Tunzelmann’s contributions to The Guardian’s “Reel History,” her pieces are collected in the 2015 book Reel History: The World According to the Movies. Her writing can also be seen on the Netflix drama Medici: Masters of Florence. Churchill is Alex’s first feature. Visit her website