What’s in store for Carolyn this season?
We’ve now closed the splinter group and gone back to join MI6 with a couple of new team members. We are trying to solve a case where a powerful media mogul has been murdered and it doesn’t seem to be a Villanelle kill. There’s now a pursuit of another killer, so two killers on the loose. In this season, Carolyn floats above a lot. She knows an enormous amount that the others don’t know, and is sometimes playing a longer game than her behaviour might appear to show.

Can you describe Carolyn?
The personality needed to work in MI6 seems very particular. It’s not warm and cuddly because you have to be wary of everything everyone says to you. You also have to be very careful of what you say, how you behave and who you love. I’m sure Carolyn loves her son Kenny, but she can’t show it because you can’t afford to have any weakness. It makes for good tension.

I suspect that Carolyn has had a series of disastrous relationships, because in the end, the love of this particular type of work dominates people’s lives completely. That makes her intriguing. Carolyn and her team are always looking for behavioural excesses. Most of us don’t believe that people behave outside of the pendulum swing, but they definitely do in Killing Eve, and nothing surprises Carolyn.

What is it like to play Carolyn?
I was keen on Carolyn being like me, and very quickly I discovered that she really isn’t. I kept trying to play her using the range of feelings that I have but I was very surprised to discover that Carolyn really only functions by not smiling and not laughing. You never know whether she’s making a joke or not, and that is great to play but it’s also very hard to play. You never know if she’s being serious or if she even knows that she’s made a joke. That’s also the power of the series - you never know what the characters are thinking.

There’s always the potential of great charm, but the characters are not vulnerable to the charms of humour. They can be quite hostile with humour and nothing is very clear. It’s the ambiguity that is the permanent knife edge on which the show works.

How does her relationship with Eve evolve this season?
Their relationship has to keep twisting. You think perhaps Carolyn and Eve would become friends because then they’d be on the same side, but no-one is ever sure of anyone’s side in this show. In theory they’re all working together, but the weird pivot of this is that sometimes you only tell people information on a need-to-know basis. Eve and Carolyn have a good relationship in one way, and a disastrous one in another. Eve needs support and encouragement, but Carolyn doesn’t give any encouragement.

Can you talk about the humour within Killing Eve?
I think what’s very new about this show is that the joke is never a button, it never lands. So you’re not ever sure where you are. There is a vacuum created around every line and it’s both exciting and disturbing to the audience. And for the performers! I have to say. We’re not playing the music of television that you might know, we’re playing a slightly off-beat music. It’s weird, a bit like syncopation.

Would you say that Killing Eve is about an ensemble of powerful but deeply imperfect women? Is this the key towards the show feeling fresh and original?
We’ve all been brought up on endless boys doing this work, and enjoying them, so it’s fantastic to have three people who are female running the good and bad of this world. It’s a joy not to play plain virtue. Women often play virtue and it’s very nice to not necessarily be good, and not necessarily be bad. Except for Villanelle who’s very bad, but it’s a morally ambiguous world.

The three women are not tied to a home or to husbands or sons. They are tied to a vision of excitement that life can be for both genders and its fantastic to have the opportunity to be able to do that. This show looks at your biggest fears about what women might be. It’s about the discomfort of a world where nothing’s sure. It’s a thriller, it is funny but it’s also disquieting. Ultimately that makes it a very fulfilling event.