You're playing a feisty police officer in Above Suspicion, the latest Lynda La Plante cops drama on ITV1. Are you the new Jane Tennison?

No, my character, DC Anna Travis, is just at the beginning of her police career; Jane Tennison had reached the upper echelons and was one of a generation of women who needed to prove that they were as good as any man. Anna resides in a more contemporary era, where it isn't about sexual politics anymore. She is strong, intuitive and overtly female.

You make her sound a bit like superwoman?

No, not at all. She's flawed and out of her depth, puking and fainting when she's called in for her first gruesome murder investigation. She tries to live up to the memory of her father, who was a legendary murder investigator.

Wasn't your own father a policeman?

Yes, although he never had ambitions to be a murder investigator. For 25 years he was a PC working in Brixton and Lambeth, South London. As a child I remember him being at the Brixton riots. I grew up with the concept of working hard and being honest.

Any parental opposition to you becoming an actress?

Like most parents, mine didn't want me to be disappointed in my life, but they also understood that all I wanted to do was to get on a stage

Any advice from your dad on the role?

Not exactly, though he did come on set. He's probably more proud of me for this than anything else I've done.

What are you proudest of?

That in the past 15 years I've been able to work consistently in theatre (After Miss Julie, The Graduate, Othello), movies (Mrs Henderson Presents, Eden Lake) and TV (He Kills Coppers) and still maintain anonymity.

Not interested in becoming a Hollywood A-lister?

I don't have fantasies about being an A-lister. That's not my dream. Still, the journey's the journey and the truth is that you never know what's round the corner.

Speaking of A-listers, you've been working with a few in recent months...

Yes, I worked with Colin Farrell in Triage, a movie about two photojournalists, and I'm working in Guy Ritchie's movie Sherlock Holmes. I play Mary Morstan, Watson's girlfriend.

You've been referred to as “theatrical Viagra”. What's your take on nudity?

On the day that you have to strip off in front of a crew there's always a second where you think “aarrghh”. But it's like jumping into cold water - it's fine when you're in. Generally, I don't have any issues or hang-ups with it.

Do nude scenes require gym time?

In my case, not. I don't even have a gym membership.

How do you keep in shape?

I walk everywhere. Very fast. If I'm in a play in the West End, for example, I'll walk there from my home in Fulham, West London, which can take an hour and a half. I also do a bit of yoga and if I have the time I indulge my passion for horse-riding. It's a passion I inherited from my mother.

Anything else she passed on?

Hopefully, her beauty gene. My mum was extraordinarily beautiful - 5ft 10in and skinny - when she was younger and she is still stunning now.

Does the “skinny gene” save you from diets?

I can put on weight with the best of them, but I don't obsess about my weight or what I eat. I can easily put on half a stone when I'm not working because I also love to cook and eat. At times as an actress I've felt pressure to be thinner. But it makes you miserable.

Happy to be curvy, then?

I'm glad that curviness is coming back into fashion because physically and spiritually it's better for us as women to celebrate and honour ourselves. There is nothing sexier than a woman who feels strong about herself and her physicality.

Are you feeling broody by any chance?

Oh, yes. Most women might turn around to look at a good-looking guy or what another woman is wearing. My double-take at the moment is babies. There is a madness that happens when your body is just saying: “Now! Right now! Whatever you're doing. Stop! It's time!” It's like a wave sweeping over you. My fiancé, the actor Jonah Lotan, laughs at me. Although, thankfully, he feels the same way. I'm definitely ready for it to be the next stage of my life.

So, in the event, natural birth or drugs?

I wouldn't be pedantic about it. If you don't need help, that's fine. If you do, why feel guilty? In all health matters I think a marriage between the traditional and the alternative is acceptable.

Ever considered therapy?

Well, I'm not opposed to it. Jonah comes from a family of psychiatrists and they are all liberal, intelligent, free-minded people. If there were things in my life that I needed help with, I'd definitely have therapy.

Does religion factor in your life?

My grandmother on my father's side is a strong Irish Catholic and my first experience of theatre was going to Mass with her on Sunday. Watching a man on a kind of stage, dressed in robes and performing a ritual, was hugely influential on what I went on to do. But my parents allowed my brother and me to make our own decisions about religion and I'm not a churchgoer.

How did you celebrate the big 3-0?

I was in Namibia with Jonah. We went horse-riding in the desert during the day and in the evening he had organised something really special. I'd like to tell you what it was, but that would be revealing something that was personal and just between the two of us. Sacred territory, I'm afraid.

Above Suspicion, a two-part drama,ITV1 January 4 and 5

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