Interview: Daniela Nardini - This life after 40

"You just feel realistic about things and your priorities change from when you're in your twenties. I was always on the lookout back then, always thinking about what came next, always looking for a nice man – other than the one I already had," she admits, with a laugh. "Now I've finally got a nice man (civil servant Ivan Stein], and I've got a beautiful daughter and it's lovely being home near my family.

"All those sorts of things that you run away from when you're younger, you come back to at this age and you realise they are what's important. Like spending time with family and people you care about. When I was younger, I couldn't wait to get out of Scotland, but now I'm back I couldn't be happier. I would love to do my work up here. All my work. But unfortunately as actors we can't just say, 'Please can I only do work up in Scotland?' It doesn't quite work like that."

Today she's looking very much at home in the snug of the Hotel Du Vin in Glasgow's Devonshire Gardens. Tall, striking and stylish in denim and black, she turns heads from the moment she arrives. While never an actor to court fame or celebrity, she's clearly enjoying our photo shoot and admits it's nice to get out and stop playing mum for a while. But toddler Claudia is never far from her thoughts and it appears her daughter is beginning to have an inkling about her mum's line of work.

"She saw me on CBeebies because I read on Jackanory. She was sitting on my knee and she looked at the telly, looked back at me, did a bit of a double-take and went, 'Mama!' She clearly didn't understand the concept but she accepted it, which was so sweet."

Just when you think Daniela Nardini has gone depressingly yummy mummy, however, she adds with a snigger, "Luckily, she hasn't seen any of the sex stuff I've done yet. I think maybe I'll wait a few years for that one…"

She has – admittedly to some family embarrassment – let it all hang out as an adulteress in the cop drama Undercover Heart, in the independent movie Festival (the sex scenes were filmed at Edinburgh's Caledonian Hotel), and as the leader of a newly founded 1960s feminist group in Big Women. And, of course, there was the sassy role that won her a Bafta – ladette lawyer Anna Forbes in This Life.

Although the drama series was the big break which took her from bit parts in Taggart and Doctor Finlay to major television success, it remains a mixed blessing. "Sometimes I think I am still a slight victim – well, not a victim, but maybe a casualty – of that particular part I played," she suggests. "It has coloured my career quite a lot and it's going to take a good old something different to break it. But I'm not particularly an actor who sits there with lots of scripts or who springs to people's minds when they are casting. In fact, I think I got vetoed to play a nun recently. The producer and director wanted me to do it, but I think the powers that be didn't believe I was nunly enough. I swear they thought, 'No she's just got far too dirty a television history, we just can't see her in a habit.'"

Nardini insists her days of being filmed in the buff are well and truly over. "I think there's a crossover point where you're just not totty any more. I find they don't want me as the mother and they don't want me as the totty either. So I'm stuck somewhere in the middle. I am slight totty in New Town, but maybe just more alternative or older totty…"

New Town is her latest TV project. It's a BBC 4 film, set in Edinburgh's famous Georgian neighbourhood, which is written and directed by acclaimed film-maker Annie Griffin, who also directed Nardini in Festival and who is herself a New Town resident. "I know it's a Scottish drama, but it doesn't feel 'kilty'. It's not Monarch of the Glen."

New Town is a darkly humorous murder mystery set in the upper echelons of Edinburgh society, and satirises Britain's obsession with finding the perfect home. The role of ruthless, haughty local estate agent Meredith McIlvanney – a woman who believes Edinburgh's priciest enclave is "future proof", since everyone wants to live there, whether they can afford to or not – is perfect for Nardini.

"It was a nice part for me to play because it was funny as well, and slightly tongue-in-cheek. Meredith's clients aspire to be a bit like her. She looks like a woman who knows the classy places to be, but actually I think Meredith has dragged herself up a bit and it's all a big faade. She's someone who is always aspiring, in that very middle-class way – wanting to be better and to have the best. There's quite a lot of snobbery attached to the New Town which does still exist and I think I recognise her type more in Scotland than down south. Maybe because I've had a child recently and I've noticed more people talking about the best bloody schools to send their kids to, before the kids are even walking. And I'm just going, 'My God, do we have to think about that already?'"

It's another strong, ballsy role for Nardini to add to those she's played before, typically policewomen and army officers. "I think it's a physical thing. I'm tall. I've got strong features. My appearance says I'm a strong person, even if I don't feel it."

The cast also includes The League of Gentlemen's Mark Gatiss, but she's the one who steals the show with another trademark Nardini hard-as-nails yet vulnerable performance. Meanwhile, the world of estate agents is one she knows well.

"We have done our fair share of moving. My daughter will be two at the end of April and she has now moved five times. We lived in London, then we moved to Fairlie outside Largs, moved twice in Edinburgh and now we've moved to Glasgow. My partner Ivan is now refusing to move again for another year.

"I've bought in Scotland before which wasn't that stressful but I bought twice in London and I found that incredibly difficult. I think it's a fairer system up here; our estate agents are slightly less duplicitous. Some of those top agents down south are trained to know all the dirty tricks and I think they are just more trustworthy up here. But I wouldn't say the same for my character, Meredith – I reckon that she was trained down south."

When asked where she stands on the age-old Edinburgh versus Glasgow stand-off, Nardini shrugs before choosing her words carefully: "Well, I'm from the west coast so I have more of an affinity with that part of Scotland and I think it's a kind of humour thing. I find there's a real difference in the humour. But then I know that people in Edinburgh will be reading this going, 'Well that's a bloody cheek, what rubbish!'"

In many ways Nardini's upbringing was idyllic. As the only daughter of the Italian ice-cream makers in the seaside town of Largs, in Ayrshire, her summer holidays were spent with her grandparents back in Tuscany. She knew early on what she wanted to be. "I used to go and see Sophia Loren and Clark Gable movies with my dad and I'd cry and tell him I wanted to be an actress," she recalls.

She had two older brothers, Pietro and Nicky, and one younger, Aldo. When she was 16, however, tragedy struck, when the family was staying in Barga and Pietro, who was just 18, was killed in a road accident. "The whole dynamic of the family changed. I think everyone just grew together more," she says.

She studied at the Royal Scottish Academy of Music and Drama but it wasn't until she was 29, in 1996, that she found true career-defining success when This Life first screened. The BBC2 drama, about a group of twentysomething, house-sharing law graduates, was so well remembered that a one-off special, This Life+10, was commissioned in 2006 to update fans on how the intervening decade had treated Anna, Miles, Egg and co.

"I think, as an actor, if you can get two or three jobs where you can go, 'You know what, I loved that, that was good and I'm very proud of it,' you are very lucky. And I did that. I have one that I'm proud of, so I'm not doing so badly.

"I suppose I've had a frustrating year of nearly getting roles, but in a way it has been good because there have been a couple of things that I thought were going to go my way but didn't quite work out, and they would have been quite a big commitment and they weren't in Scotland. So, in retrospect, maybe things are just working out as they should. To be honest, there isn't an awful lot on that makes me go, 'Oh I wish I was in that.' I'm enjoying American TV dramas at the moment which seem to be much edgier. I think we need a bit more of that in this country, there's not an awful lot of risk-taking on British TV at the moment."

And Nardini does like to take risks – she's sought out low-budget, high-integrity movies such as her film debut in Elephant Juice, written by This Life creator Amy Jenkins, and Cargo, the story of four Croatian asylum seekers, made in late 2002. Four years ago, she returned to the stage and received plaudits for her role as Marlene, Caryl Churchill's go-getting career woman in Top Girls at the Citizens Theatre.

As for getting older, turning 40 last year didn't faze Nardini: she celebrated with friends in France. "I did not want any hideous surprise parties," she says, insisting that the passing of time is not something she ever worries about.

"It'll probably stop me having another child," she points out. "But I don't mind ageing. In fact, I don't really think about age. When I was about 37 and I didn't have a child, I did think, 'Oh God,' and started to panic a bit. But because things have happened in my life and it's good, now I just want to continue in the same vein. I still get people asking me about This Life but that doesn't bother me now, either. I just think: at least they are still recognising me and that I don't look that much older.

"I think being a mum has calmed me down a bit. I'm still basically the same person but I suppose you get a bit more patient. If there's someone that doesn't want to do a single thing that you want them to do, then you just have to go, 'All right, I'll have to accept this.' That's quite a challenge for someone like me because I was quite impatient beforehand. So maybe I've improved slightly."

So, is Claudia showing any signs of following in her mother's footsteps? Nardini grins and thinks before replying: "I don't know about her becoming an actress but she's very headstrong. I certainly don't have any worries about her being a shy, retiring little thing…" Hmmm. We wonder where she gets that from?

New Town is on BBC 4 on Saturday 14 February at 9pm.