Charity Wakefield says she had a great time filming alongside Jack Whitehall.

Can you tell us about your character in the series?

Leah is crazy and she doesn't say no to anything. She's Barnaby's sister but while he is an upstanding young man who is self-aware and kind, Leah is the opposite.

She's a really tough character who you get the sense has lived all sorts of different lives all over the world. She's whip-smart, well-travelled and, like her father, she is not everything she seems.

At the beginning of the series, Barnaby finds himself in deep trouble. Leah comes home to help him out, but when your worst possible nightmare of a family member is trying to do their best to help you, sparks can fly.

Can you relate to Leah?

I have definitely had moments in my life when I have felt like her - when I have felt mischievous and like I could do whatever I liked. Ultimately, though, I haven't because I think I am a more responsible person than she is. I think we have all got a side to us that wishes we could just travel and do whatever the hell we like but most of us have more of a sense of home and responsibilities.

Did you enjoy the role?

The fun in Leah is that she constantly has one up on her brother. The writing is just brilliant. Jack and Freddy write great characters and as soon as you think one has status over another the conversation is flipped up.

It was brilliant fun to film because you find yourself in fits of giggles the whole time. The choice of characters and putting them in the same room together is funny enough, let alone sending them on this insane, action-packed journey. It's a great story and I think it will appeal to lots of different types of audiences.

We've come to associate you with period dramas. Did Bounty Hunters appeal to you because it was very different?

Yes, it was also slightly nerve-wrecking because I am used to doing roles that are based on a story that's real, are a known historical character or are from a novel that's been adapted for screen. In all these instances you have got something very firm that you can research but a character like Leah is created as you go along. You have the scripts and you have her back story but it's very much about finding out what works. There's nothing in history to tell you that it's not right.

Your costume must have been more comfortable than the one you wore as Mary Boleyn in Wolf Hall...

One hundred percent. My costume is a dream. It's super comfortable, slouchy, urban and cool. We decided that Leah was someone who has a bit of money but is also a magpie. She has travelled around the world and picked up things here and there. She probably ditches them now and again and gets a whole new wardrobe in a charity shop.

She also has this crazy birds' nest-type hair that she doesn't care about. It's the first time ever on a job that I have been able to keep my hair pretty much natural and it hasn't been that fussed with.

Are any of Leah's clothes vintage?

Yes, we decided she would have some and I told the costume designer I had this store of wacky, weird and wonderful vintage pieces so we raided it. Some of the stuff made it on to the show, in particular a red top I auditioned in. It's nice when things like that happen because it gives you a sense of ownership over the character. You feel like you are building a character from scratch.

There's plenty of action in the series. Were you involved in any stunts?

No, but I was often in the room when stunts happened, that's because Leah is one of those people who always manages to escape the danger herself. She's a semi-addict, though, and smokes a lot of drugs so I had to do quite a lot of smoking. They have to give you herbal cigarettes because you are in the workplace and you can't properly smoke - no real drugs were used in the making of this show!

What was working with Jack Whitehall like?

Jack is so annoyingly talented. He is so young as well, and he looks great. He's really nice, too. It's so unfair. It's just galling. We were filming one scene and it had been a long shoot and the sun was setting and we didn't have much time. It was written that my character got unusually emotional and cries a single tear. Just before we went for the shoot, Jack came up with a way to make the scene funnier but it was so tough because I knew it was going to be funny but I was supposed to cry. Jack was kind enough to see that it would be difficult and asked over the walkie-talkie if we could back the car up to give me a bit more time. I will always remember him for that. He is on it and he is kind and generous. I was really lucky to work with him.

You were in last year's Doctor Who Christmas special. What do you think of Jodie Whittaker becoming the next Doctor?

I couldn't be more thrilled. She is one of my heroines and I know she will be fantastic. She will do something interesting and different to anyone else before. I find it amazing that there has been negative reaction about a woman being cast in the role. I think it will start to open more doors for women to be in these brilliant heroine roles. And loads of girls will be able to dress up as Dr Who now!