Halo's Natascha McElhone: 'Halsey's brain goes to places it shouldn't go to!'

"I suppose it's that she's a scientist, and a maverick, which is the opposite of what I do. There's an awful lot of waffle that you can get away with being an actor, or someone in the humanities, whereas as a scientist you have to prove everything, and that interests me. And a good scientist doesn't just ignore conventional wisdom, but probably makes a special effort to break it — she has a brain that is in the habit of going to places that it shouldn't go. I guess her moral construct is different than anyone else's, because she's able to imagine a world that I think most of us can't yet."

"A lot of the conversations I had with the showrunner, writers and creators were around pacing, and remaining inscrutable for as long as possible, so you didn't get into the arena of just playing an archetype, the sort of moustache-twizzling Cruella De Vil or whatever. It would have been quite easy to go in that direction, I think, and then the audience would be able to write her off and maybe not bother to see things from her point of view. Hopefully what the show has managed to do is to put the audience in a different driving seat for each of the storylines.

"From Halsey's point of view, she's able to see life as we don't yet know it. Perhaps like Galileo, or someone being thought of as morally reprehensible in her own time, she will one day be seen as someone who saved humanity, by augmenting and sacrificing the lives of a few people in the short term, she saved the lives of future generations that she'll never meet. You could say, there's no direct approbation or social benefit she's getting from that, so it's altruistic. I find that fascinating — the philosophical side of how we judge humans."

"As with a lot of scientists, there's a very strong ego at play, but I think her curiosity will trump that ego. So she marvels when John [Master Chief] or Cortana [the AI that Halsey created] overrides the system that she thinks is pretty bulletproof — but the exponential growth of an AI is such that she'll end up surprising you. I think all those questions that are posited through the show are interesting and relevant to our lives. Like all good sci-fi, you're exploring morality catching up with technology. If we're going to put our trust in synthetic intelligence, we've got to do some big thinking."

"I did due diligence — we did a sort of Halo boot camp, and I played the game a little bit, and my half-brother is a gaming journalist. I spent a day with a guy who'd spent three solid years of his life playing Halo —  so that was really instructive. I did read up about the lore, but in a sense it wasn't so relevant for the character that I was playing. The game is huge — the number of websites that there are, the backlog of information that there is, it would take you years and years to read! This gave me a respect for the fanbase — these people are really committed, it's like becoming an expert in Greek mythology, there's years of accumulated wisdom around these characters and stories."

"I realise it doesn't please every fan that we've even had the hubris to go and make a TV show from it — which is fine, you don't have to watch it, you can continue to play the games, there's no obligation! 

"But I think if you've got a great storyline, this is what we do now — we tell it in many different forms. I'm sure there are always purists who want to stuck with the original material, but it's been really fun to come into that world which I probably wouldn't have delved into otherwise."