Naturally then, the film comes down on her side and Knightley as her portrayer does alongside her.

Its all the more interesting for that.

Their stories otherwise run in parallel to each other.

I definitely remember the run-up to the Iraq War.

It seems like Katharines story was swept under the rug in some ways.

Were you familiar with her or what shed done?No, not at all.

I think when that story hit I was in the States.

Youve played plenty of real people before, but the vast majority of them are long since dead.

Did it change your process at all to be playing a woman still very much alive?Certainly.

I suddenly got very self-conscious.

Gavin said right at the start he didnt want a characterization of Katharine.

I look nothing like her…But what was super helpful was meeting her before.

We had lunch beforehand.

Given what she went through afterwards, I was really interested by that.

I said Would you do it again?

And she said Yes, absolutely.

That brought home the seriousness of the whole thing because shes still bound by the Official Secrets Act.

She has an absolute morality and thats what she followed.

That was what I used.

What about others in her life her husband, the journalist Martin Bright, etc.

did you meet them?Her husband and daughter came to set.

They were all on set the same day.

I had a long conversation with Martin while we were on set just because hes fascinating to talk to.

They were very, very supportive so that was hugely helpful.

So I thought those were both the most difficult and the most fun to play.

I found those three scenes rather terrifying but totally great at the same time.

Im a great believer that its there for a very, very important reason.

But I really believe in the necessity of investigative journalism.

This film definitely is a celebration of that.

Right now, thats very important.

Me and Gavin had big conversations about how intelligence services are meant to work.

How does it work if people do give up secrets?

With Katharine, this is all slightly different.

Shes very particular about this shes one of the only whistleblowers whos only ever leaked one very specific document.

But she didnt do that.

And thats very important to her.

She wasnt putting field agents in danger.

I understand the necessity for secrecy within intelligence services.

How do we hold people accountable?

And what are our democracies worth if the people in charge are not held legally accountable?

Its super interesting questions that all of these [things] raise.

It makes me realize my thinking isnt black and white on this.

I did look into other whistleblowers.

He seemed an ocean away.

I felt like I was drowning.

It was a nice benchmark for having learnt a lot in the last decade.

(Laughs) I think you know the answer to that.

I dont think so.

I could obviously be wrong, but it doesnt look like it.

It looks like were in quite a similar situation.

Yet it still feels like we dont have the conclusion of this story.

Were still very much living with it.

We dont know how it ends.

But as far as where the planet goes after this, who knows?

We live in exciting times.

Wouldnt it be nice if it was boring?