Isy Suttie explains how she creates back stories for her characters.

You play Nat in Channel 4's new sitcom Damned. What's her story?

She's a temp who comes back and stays with the office. Some would say she's quite scatty and gets the wrong end of the stick a lot of the time, which is true, but when I play her I like to think of her as someone who lives on a slightly different plain from most other people.

She's really bad at the computer, and people have to tell her how to do pretty basic stuff, but she's really quick at texting. We put in stuff like that because I didn't want her to be a typical bimbo. I thought of her as someone who, perhaps, had difficulty empathising with people and saying the right thing. Who's quite good in some areas and perhaps, with guidance, could be a really good social worker if she got taken under someone's wing. But she's often put in situations where she says the wrong thing, or reveals something she shouldn't.

Comically, she's a good person to go against Rose and Al, because she rubs them up the wrong way quite a lot of the time. She was really fun to play, because we could kind of go anywhere with it, just because we didn't want her to be that stereotypical bimbo.

Do you invent a backstory for someone like Nat when you're doing something like this?

Yeah, I always do. Even when I've got a small part in something, I always write a bit of stuff for myself and think about it. I always give them a surname if it isn't in the script, and think about how many brothers and sisters they've got, and what kind of upbringing they had, and whether they went to uni, whether they're happy, and whether they're where they want to be.

What I thought about Nat was that she'd worked as a receptionist at a garage for a long time, and been having quite a long-term affair with a married guy. She knew in her heart that he wasn't going to leave his wife. So for me that was always underscoring things a bit.

We're in the back of shot a lot in this show, there wasn't much downtime, so I'd be in the background texting a lot. And when I was texting, I was always texting him, and trying to meet up with him and stuff like that. I do always think about that, because it helps me so much. Especially on a show like this, where it was pretty loose. It was great to have that back story in place, it helps me be more comfortable.

So when you're in the back of shot and texting, are you actually typing something out?

Yeah. I always do, yeah. I think I'm a bit anal about that side of things. I like to stay in character the whole time. Even if I didn't know whether or not I was in shot! I think it's actually harder to not do stuff in character. It uses up more energy. So if you've got to write or type or text something, it uses more energy to write a shopping list or whatever than it does to stay in character and write what she'd be writing.

Had you worked with Jo before?

Yeah, but only at benefits [gigs] and stuff like that, and a read-through. I'd have a bit of a chat with her, and we live quite near each other, but I didn't know her extremely well. I got to know her very well on this, because we often got the same car, living so close together. She's fantastic. She's so kind, and has a real childlike glee in the foibles of life, that completely delighted me. She's such a positive person to be around, and very, very generous.

You'd worked with Alan on cooking sitcom Whites. Are you forever destined to play characters who are ordered around by Alan Davies?

I hope so! There are many worse things I could be doing. That's true, though, I hadn't thought about that. Though I suppose, with Whites, he really got to shout at me and order me around, whereas with this one I feel like Nat's got a slightly higher status than Kiki did in Whites. But I'm not complaining. Maybe we could do another remake of Dad's Army, and he could order me around in that as well.

Working in children's services is not an easy job. Does that inform a lot of the comedy in this?

Yeah. I think they have advisors who worked in social services who were telling them about real cases, so the scripts are always true to life. I think they don't shy away from the bigger issues in Social Services. This doesn't feel like a light-hearted look at social services, this feels like you're really in the thick of it, in terms of the difficult decisions that have to be made, and the complexities of cases.

I just watched this drama called Don't Take My Baby by Jack Thorne, about a disabled couple who face the possibility of having their baby taken away from them, based on real life, and it's children's services who would do that. I was watching that and thinking "That's the kind of case that's featured in our show." It felt like the writing made the most of the opportunity to explore those real life cases in an interesting and funny way. Hopefully the warmth of the writing earns the right to be able to talk honestly about those cases, so that it isn't just jokes, and that enriches the comedy. It felt like that when we were making it, and I was really pleased it didn't make light of anything.

You're known to legions of comedy fans as Dobby from Peep Show. Do you get that shouted at you a lot?

I used to more. I've noticed over the last few years that more people are saying "I really liked your radio show" or the book I wrote, which is lovely. But, to be honest, I loved playing Dobby, it was a dream come true for me to get that job, and I'll always have such affection for the show. I never mind. I never think "Oh no, they remember me for just that." I think if you're doing something else, if there's movement, and you feel like you're challenging yourself, then you really don't mind.

It's not like you were on Grange Hill and then you go and work in a shoe shop and people come up to you 40 years later and go on about Zammo. As long as you've got an idea to do something that you're excited about, that's the key thing. You're alive, and you're challenging yourself. But I did once get a horde of about 20 people chasing me along the South Bank shouting "Dobby!" But that was when I was first in it, and I remember thinking "Oh my God, is my life always going to be like this." It was the only time it's ever happened.

Your comedy often has a musical element to it. Is writing and performing music important to you?

Yeah, it's kind of bound up in me, I suppose. I've been writing music since I was 11 or 12, so I can't ever imagine not doing that. I did write a couple of songs recently, but over the last few years I've not written as many as I used to write. But I'll always include it in what I do live. I think it's quite hard to make songs work on telly, though. Flight Of The Conchords did it, and I still need to see My Crazy Ex-Girlfriend. I think I'd one day like to write something for telly that has songs in it. Toast does it really well. That's a remaining ambition. It's much easier to do it live. But I'll always do music.

And, as you mentioned, you've written a book as well. That's just showing off now, isn't it, on top of everything else?

Well, I had a baby as well, and it's really quite a good thing to do when you're pregnant. Weirdly, the book is about not settling down and having kids, but it takes so long to write a book that during the time of writing I settled down. I really enjoyed it - routine wise, I'd get up and just start writing, without checking my phone or my emails, that was what worked best for me.

Lastly, if you could only do one of acting, stand-up, music and writing, which would you stick with?

It changes every day. I can tell you what I'd say today: Acting. But if you ask me in a week I'll probably say something totally different. Acting or tennis. I always wanted to be a tennis champion.

You don't think you might have left it a little late?

No, I think if you follow your dreams, anything's possible. I only wanted to be a tennis champion for about six weeks, when I got into it because of Wimbledon. I'd plan out all my hairstyles, and how I'd make people laugh while I was playing. It was just another way of showing off, really.