What was your initial approach?SARAH GREENWOOD:Its history we know quite well.

A lot of gaps had already been filled in, but this film is about capturing themood.

Theres also the counterpoint to the downfall: the look of something like Valkyrie.

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Sarah Greenwood/Focus Features

[Churchill was] in a war room in a basement…

The Downing Street set is actually a derelict estate.

It doesnt look like Downing Street, but it has thefeelingof Downing Street.

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Sarah Greenwood/Focus Features

We did the same thing with the war room.

We took that inspiration and created our war room on a set of two stages.

You never knew quite where you were.

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Sarah Greenwood/Focus Features

The same goes for Buckingham Palace.

All the plasterwork was there, but again, it felt like it hadnt been touched for 70 years.

Were not a documentary: were telling our story with our atmosphere and our feelings for the subject!

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Sarah Greenwood/Focus Features

Were the politics and the intimate detail [to their action]… but we cant compete!

Though we did use the same five boats thatDunkirkused.

Ill tell you why.

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Sarah Greenwood/Focus Features

Theres a little boats association [in the U.K.], and they literally have the boats from Dunkirk.

Thats such a nice bond the two films share.Totally, and this is my whole thing: I loveDunkirk.

Its amazing, and were the bookend.

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Sarah Greenwood/Focus Features

I think the two should be seen together, particularly for kids in education.

Theres an amazing togetherness, really.

In years to come, it will be a great thing to see them together.

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Sarah Greenwood/Focus Features

I also love how intricately character develops through Katie Spencers set decoration.

Our cigars were the same cigars Churchill actually smoked.

Darkest Houris in theaters now.

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Sarah Greenwood/Focus Features