One of the subplots added by creator Adrian Hodges for the 21st Century incarnation of Survivors concerns "the Lab", a mysterious place run by the driven scientist James Whitaker, played by Nicholas Gleaves. Seen mainly at the end of episodes during the first season, the Lab, and Whitaker himself, have become key parts of the second season. Paul Simpson spoke to Gleaves on the set of the fifth episode...

From what we saw of him in the first year, you're not playing a very nice guy. How much did you get told about who and what Whitaker is before you came on board?

I had a conversation with Adrian on the phone before we started, and he told me that I was playing a brilliant man who was trying to rectify a desperate situation. That was probably all I got. But that was a pretty good starting point.

You play him as almost autistic in his relations with other people: he seems disconnected from those around him...

He's very unemotional. That's what is so exciting about him in the midst of this series. The Family that we follow through this piece, they're nothing but emotional. They're all emotions – Abby is raw, so wonderfully at the behest of her emotions.

Whitaker is the exact opposite of that. He is very self-contained in a situation that is unbearable. I think what he's done is really rein himself in and then gone, "Right, what can I do to make this better?" Emotion to him is the enemy, and he's just not like that.

Do you think that he feels that a human life is worth no more than a lab rat's?

Human life to this man is now only one per cent of what it was before. There has been a holocaust that is just absolutely gigantic. His thinking is "What's one more death if we can turn this around, find a vaccine and then make sure of it before this virus mutates?"

Remember, the virus is not finished. It's moving around, and if we can find some sort of vaccine that can contain it then really any scientist, any person who cares about human life, who has any power about it, would make that sort of choice. They were never difficult choices for me, and I think Adrian writes them in a completely logical way.

What is he supposed to do? "I can't kill that dear old lady because she's a dear old lady?" But if he does do it, then explores her body and finds some answers, he can start to rebuild this place again. It's a no-brainer really.

Does he bear any responsibility for what's happened in the first place?

I'm not prepared to say anything about that – no comment.

How much time did you spend filming the scenes for the first year? Were they all shot at once?

Not long: in every episode, I must have done a day or even half a day. I think the way it was written, they didn't know where he was going to end up. There are a million logistical reasons why you can't shoot all the scenes at once. Anyone can find themselves available for half a day.

What did you think of the changes we see in the first couple of episodes of the second year?

There is a massive leap, and I couldn't believe my luck. From an acting point of view, I just thought, "My gosh, someone up there loves me. They've taken this man and they've turned it up to volume 10!"

I've always liked the show, even from a punter's point of view. I just love the idea. It's a basic childish imagination game. Everybody's dead but you – what do you do? It's just fabulous, and to put it in an action, sci-fi genre works incredibly well.

What do you look for in a script?

A journey in a character from A to B with as many twists and turns as possible, because then generally you're in the realm of good writing.

What would you think if you met Whitaker?

I think I'd be quite intimidated by him really because of his self-possession and his intelligence. It's certainly much bigger than mine. When I've come across people who seem to operate on an intellectual plane, they are a bit intimidating but also interesting.

You might also feel sorry for him because the lab is where he's most comfortable – and maybe that's not such a good thing. When you've got to live in a real world and deal with human relationships, people who are all about the brain are not necessarily whole.

Do you see him as a character with a long future, or by the dramatic nature of the character, do you think too much of him would run the risk of his becoming a James Bond-like villain?

You always need someone to kick against, you always need some authority. You always need some drama, so that means two opposing sides at least. As long as they want me, I will definitely be here.

And you need someone to try and sort the situation out. There is a scientific route to be explored, and this Family don't know about that. They wouldn't know a bloody test tube from a Bunsen burner, so you have to have someone to try.

Do you think that makes him a necessary evil?

Necessary to regenerate things again, if indeed that was ever a possibility, yes.

But these dramas can twist and turn. Even five minutes of a drama can be a terribly long time, and you can turn things on their head. Things change – people can come in and out of favour. You can maybe even see him in the gang...!

Survivors is currently airing on BBC One on Tuesday nights.