Christie Watson: 'Life, death, what makes us human – nursing and writing are about the big questions'

The winner of this year's Costa First Novel Award isn't about to give up her day job, she tells Nina Lakhani

Christie Watson at her London home, where she lives with her Nigerian partner and their two young children (Jonh Lawrence)

Christie Watson is baffled by all the fuss. For the winner of this year's Costa best debut novel award, being a writer and a nurse are perfectly compatible. In fact, she can't envisage writing without her day job for inspiration. "I don't think nursing is that unusual a day job at all for a writer, because the two cross over massively. They both involve thinking about life and death, and what makes us human; they both involve the big questions."

For her, motherhood poses much more of a challenge to her prose. "For any writer who's a mum, that's very difficult to juggle, it's tricky. It's much more challenging than juggling writing with nursing which fit perfectly together."

Tomorrow Watson, a part-time paediatric resuscitation nurse, will find out whether her wonderfully crafted novel, Tiny Sunbirds Far Away, has won the Costa Book Award. She started writing just after the birth of her daughter eight years ago and her own family relationships ooze out of every character, deftly navigated through the complexities of modern Nigeria – birthplace of her partner.

The book tells the story of a young girl, Blessing, whose life is ripped apart by her father's affair. The tale is essentially about the young protagonist trying to make sense of her life amid Nigeria's social and political turmoil, and who is protected by strong relationships with her brother and grandmother.

Some have questioned whether she, a white British woman, is qualified to write an African family's story, questions brushed aside by Watson. "The grandmother is basically a mixture of my mum and mother-in-law; if they morphed into one, she would be that person."

Born in Stevenage in 1976, Watson was raised on a council estate by her in-and-out of work father and nursery nurse mother.

A self-confessed "teenager from hell", she left home at 16 after achieving a miraculous seven GCSEs – a miracle because she never did any homework. "I woke up on the morning I turned 13, literally, and I hated everyone, particularly my mum."

For several years there were few overt signs of the potential she would later tap. She shaved her hair, embraced moodiness, didn't speak to her parents and moved in with her boyfriend, yet at the same time became politicised in the old-fashioned teenage way. "I was a pain in arse. I always had a banner, a placard: one week it was anti-vivisection, the next veganism, everything."

After more than a few ghastly part-time jobs, including oven cleaner in a market café, she landed upon what at the time felt like career jackpot: working in a video shop, where she swapped films for free Chinese food with the takeaway man. "It felt like the perfect employment that I could do forever, but then the shop shut, which was probably my saving grace as otherwise I could still be there now, thinking 'Yeah, I've got free Chinese food'," she laughs.

Amid the adolescent rebellion, she never lost her passion for books and became enchanted by African-American storytellers such as Alice Walker and Nella Larson. Writing was something she fantasised about, but higher education was never on the cards.

Her first experience of caring came at 16 while volunteering with Scope, then the Spastics Society, at a residential home. Here she met nurses for the first time, and at 17, applied for nurse training in London. "And that changed my life – I grew up overnight. The training then was like being in the Army, which saved me." That military discipline later proved crucial to her writing.

Watson met her Nigerian paediatrician partner 11 years ago when they were both working at St Mary's Hospital in west London. They now live in a bright, suspiciously tidy terraced house in south-east London with their two children, aged eight and five; their 18-year-old daughter (Watson's step-daughter) is there most weekends.

The pair have never got round to marrying; however, her in-laws, whom she adores, conducted a wedding ceremony in their absence, with an imam, and sent the VHS recording as proof.

Watson has fallen deeply in love with Nigeria over the past 10 years and doesn't rule out living there. She wants her children to someday live and breathe Lagos like they do London, though the current civil unrest and escalating violence means the plan is on hold.

Tiny Sunbirds Far Away morphed out of the first short story she ever wrote for a creative writing MA at the University of East Anglia.

So far only their middle child is showing creative leanings: "She wants to be a writer, or a mermaid – she's still in two minds," explains a delighted Watson. "I go to school and the teachers say 'Oh you're moving to Las Vegas?' or 'Did she go swimming with sharks?' Every week I hear another fantastical story."

She experiences her fair share of guilt, worried that she is selfish to write and nurse, both of which she loves, but which mean she isn't always at the school gates and relies on Mr Kipling to bake the cakes. "I do have the classic mother guilt, but then I see how my girls look up to me as much as their dad and they think they can do anything too."

The unavoidable juggling has made Watson an efficient writer, and she insists that writer's block is a luxury a working mother cannot afford. "The kids are young, they have fights, and inevitably someone has a temperature or a rash, or someone is not someone's best friend any more – there is always some drama. I've had to learn to switch off quite quickly and sit down whenever I can, snatch a bit of time and then go back to the kids." After suffering from the same anxieties that assail many successful debut novelists, she is now into the groove of the second book and has almost finished a first draft. "I am now seeing the characters; I've started dreaming in the book, and that's a good sign." She won't give much away, except that the story is again quite political, mainly set in London, with occasional journeys to Nigeria, and could be published before the end of the year. Inevitably though, it will be, like the first, about her life: a mixed-race multi-faith family making sense of their world.

Watson is genuinely warm and caring – she lays on breakfast and offers a lift back to the station – and is revelling in the opportunities to speak about her bugbears. That aside, she seems slightly underwhelmed by the Costa accolade. "It's nice, but I felt much more emotional and proud that Cassava Republic [a West African publisher] is publishing the book locally." The £5,000 cheque she is guaranteed to collect tomorrow will come in handy, she says, as their boiler blew up over Christmas.

Last week, she took part in a debate on British identity and diversity hosted by the Museum of London. "I am still very positive about Britain because we are a British family and we are very proud that not only can we exist in a place like this, but we can thrive."

She has also been propelled into the role of nursing ambassador, a lonely voice sticking up for the profession she loves amid a steady barrage of care scandals and withering criticism from even the Prime Minister.

"It's always helpful to discuss how standards of care in the NHS can improve but those discussions must include what the Government is going to do to increase the numbers of nurses and take away some of the pressure to save money. In terms of hourly ward rounds [David Cameron's new idea] I just don't see how that would ever work."

Watson is one of those people who takes life her stride, and comes across as if she's loving every minute of it. She fundamentally needs her day job for inspiration, and imagines the full-time life of a writer as a lonely one. That might change, but right now she can't imagine one without the other. "How could I give up something that I've done since I was 17?" she reasons. "I need to go to work."

A life in brief

* Born in Stevenage in 1976, Watson was raised on a council estate by her father, who had a variety of different jobs, and her nursery nurse mother.

* Leaving school at 16, she volunteered at charity Scope before beginning training to become a children's nurse at Great Ormond Street Hospital, aged 17.

* In 2001, she met her husband, a Nigerian paediatrician, when they were both working at St Mary's Hospital in London.

* In 2007, she won the Malcolm Bradbury Bursary for a place on the renowned creative-writing course at the University of East Anglia for a short story that became the basis of her debut novel, Tiny Sunbirds Far Away.

* She still works as a part-time nurse in London in two teaching hospitals, and has spoken out about the Government's cuts to the NHS.

Working writers

Arthur Miller

The family of the US playwright lost money in the Wall Street crash in 1929, prompting him to take on work as a bread delivery boy. He also worked as a Brooklyn Navy Yard labourer and as a box assembler in a beer factory.

Agatha Christie

The crime writer's excellent knowledge of poisons came from time working as a volunteer nurse in a Red Cross hospital during the First World War.

Philip Larkin

The renowned poet became librarian at Hull University in 1955 – and held the job until his death 30 years later.

Sylvia Plath

The poet and novelist worked in Massachusetts General Hospital as a receptionist while studying in the evenings.