Nancy Carroll: She's on the money

A play about the expenses scandal opens tonight. Award-winning actress Nancy Carroll tells Alice Jones about playing an MP's grasping wife

Two years ago Nancy Carroll was named Best Actress at the Olivier and Evening Standard Theatre Awards, for her heartbreaking performance as Benedict Cumberbatch's wife in After the Dance. She was eight-weeks pregnant by the end of the run at the National and went straight to the Almeida to star in House of Games for three months, during which her nausea was so bad that one night she was sick on her co-star. By the time the ceremony for the Oliviers came round, she was eight months pregnant. The shock of winning set off her contractions and she hardly made it to the podium before she had to stagger into a taxi and go home to prepare to give birth.

In other words, Carroll, 40 years old and 15 years in the business, is a trouper. The trials and tribulations of her latest play, The Duck House, are so much water off a duck's back. A frenzied farce with the slapstick of One Man, Two Guvnors and the topical jokes of Have I Got News For You, it has been touring the regions before it opens in the West End tonight. The other day in Malvern, a door stuck and she couldn't get on stage for two minutes. The week before, in Guildford, she threw a prop and knocked out a light. "I turned round and said, 'It's alright I don't think they noticed'. The audience was hysterical for three minutes."

The play is written by Dan Paterson and Colin Swash, whose combined credits include 40 series of Have I Got News for You and 12 of Mock the Week, and is directed by Terry Johnson. Ben Miller stars as a Labour backbencher who is planning to defect to the other side when the expenses scandal breaks. Carroll plays his grasping, bubbly-guzzling wife, Felicity. "Oh gawd. It's the most fun I've ever had on stage. Slightly too much fun. There's a lot of corpsing going on," she says, sounding rather like a jolly sixth former. She looks like one, too – an actressy jumble of eccentric scarves, unruly auburn hair and freckles.

Although Carroll is well-versed in comedy – she starred in See How They Run in the West End and recent credits include The Magistrate at the National and The Recruiting Officer at the Donmar – the show has required a shift in gear. "In TV everything has a much faster turnaround. We are quite precious by comparison. This is quite cut-throat. If it's not funny, you say so, and you move on. The rehearsal space is usually a very safe environment in which you can expose yourself, try things and not feel stupid. So that was quite a shock."

Carroll does not get nervous, although she has suffered from stagefright in the past. She was performing with the RSC in Newcastle at the beginning of her career when it hit. "I could just see the reflection of every pair of spectacles in the audience. It all became slow motion and as every single word came out of my mouth, I wasn't sure it would. So terrifying."

It has happened since. In Arcadia in the West End four years ago, she kept stammering on a certain line. "It tends to be fleeting moments, really. It's a very leftfield experience. It's because what we do is such a bizarre physiological experiment. They say that going on stage for the first time in a show has the adrenaline equivalent of a minor car crash. It's fight or flight. So it's about controlling that adrenaline. It's funny, when you don't experience it, you feel like you haven't really given your all."

She still remembers her debut performance. She was three years old and did a tapdance at Brixton Town Hall. When it came to her big moment she refused to go on stage without her mother. "So she had to stay behind the curtain and do the whole dance with me," she says. She grew up in Herne Hill, south London, where she still lives, and went to Alleyn's School, where she was in all of the plays. Well, almost all of them. "I remember being terribly upset once about not being cast and flailing across the school playground, thinking my life was over. My drama teacher came and grabbed me and said, 'Promise me it will never mean this much to you again.' I was about 14 at the time." Did she heed that advice? "You do have to have a thick skin; that allows you to stand up and brush yourself off… But sometimes you'll get down to the last two for something and someone will say, 'I want A not B.' And it's devastating. Completely devastating."

After school, she followed her parents – both graphic designers – and went to study fine art (her brother also works in the arts, as a film-set designer). She spent a year in Italy learning how to mix her own paints and stretch canvasses before starting at Leeds University, where she found the course too conceptual and the life of an artist too solitary. She wanted to create in company. So she applied to LAMDA, paying for her first year with her fee from a tampon advertisement. After that, her first professional job was in An Ideal Husband. "I literally left drama school and was in a read-through with Cate Blanchett, Minnie Driver and Rupert Everett. I thought, 'Well, this is all right.' And of course it didn't carry on like that at all."

Instead, she went to the RSC, to play "various hags and understudy squirrel" in The Lion, the Witch and the Wardrobe before quickly climbing the ranks. She met her husband, the actor Jo Stone-Fewings, when they were both filmed as part of a touring troupe for the BBC documentary In Search of Shakespeare. They met on the first day of rehearsals; nine days later they were engaged. The proposal happened at Shakespeare's school, in front of an audience. Carroll was wearing a long, white dress, "and Jo said, 'We could do it now.' And I sort of knew what he meant. It was just sort of instant, and very un-mad. It was a calm knowing, really. If you're in the right frame of mind, it's an animal connection. That was 11 years ago."

They now have two children – Nelly, 5 and Arthur, he of the Oliviers contractions, 2. Nelly had a scarcely less dramatic gestation. Carroll was performing in The Enchantment, again at the National, again as a suicidal heroine. At the final performance, she was nearly six months pregnant. "It was hilarious. I was playing a virgin and getting fatter and fatter by the day. Every night my dead body had to be carried in a wet, heavy 19th-century frock. They were ready to bring in the forklift truck by the end."

She and her husband now take it in turns to work outside London. "With a family, you're constantly balancing the books and there are moments when it's quite scarily unbalanced. At that point you question fundamentally what it is that we're doing because you feel that you're putting your kids' stability in jeopardy. You feel that your careers are luxuries."

After the Dance and the awards were a game-changer, she says. There was talk of the show going to Broadway but the timing didn't work for Cumberbatch. "Quite rightly he wanted to seize opportunities to do more stuff on screen. Sometimes it's lovely to leave moments as moments. Rather than milk them for every single ounce of life," she says smoothly. She would love to return to Rattigan and play Hester Collyer, the tragic heroine of The Deep Blue Sea, but worries that she is not quite old enough yet. "I'm a great believer in earning the right to things. Having been on the planet a little bit longer, you have an emotional advantage."

The disadvantage, of course, is that over the age of 40, parts for women start to dwindle alarmingly. "It's not for the fainthearted, this profession," she says. "Certainly there are fewer women's parts. And often, even if the part is written for someone in their fifties, they cast someone in their forties. There are a lot of very brilliant actresses for whom there isn't a lot of work. From your mid to late forties to your mid to late fifties, it's terribly hard."

She hopes that the rise of female artistic directors such as Josie Rourke at the Donmar and Vicky Featherstone at the Royal Court might make a difference. "What's brilliant about those women is that they're working as women. Perhaps they can oversee a shift. As much as employing women, it's about representing women. We need to harness the emotional openness and potential of women at that particular part of their life, and write about it. Women don't just go silent for 10 years. Far from it. I think you come into your own at that point, in fact. My husband is always telling me that that's when you hit your sexual peak. I'm rather looking forward to it."

'The Duck House', Vaudeville Theatre, London WC2 (0844 412 4663; the-duck-house.co.uk) to 29 March