Debut novelist Jason Donald tells why he wanted to make growing up under apartheid seem the most natural thing in the world

CLOSE YOUR EYES AND REMEMBER being 12. There are people who can't do that, whose memories have just drained away, who can't recall what it felt like to be on the cusp of the grown-up world while still not understanding vast swathes of it. And every time Jason Donald meets one of them, he's surprised because he's just the opposite.

Choke Chain, his astonishingly assured debut novel, is the proof. In it, Alex, his 12-year-old protagonist, is told by his mother that God has put a special camera in our heads, and that all we have to do to remember anything is to blink our eyes and say "Click". There's a credibility about Donald's prose that suggests he might have been blinking and clicking for years.

To Alex's brutal garage mechanic father Bruce, life is about "winners and losers – whatever it takes". In practice, this means forever doing down the little guy, bullying his way to refunds from shop assistants, scamming car insurance companies, never taking no for an answer. If that's winning, losing is having to make time for other people, feeling empathy, care or concern for others, not being able to enforce absolute obedience.

What gives this an added edge is that the novel is set in apartheid South Africa, where Bruce's swaggeringly boorish ideals of fatherhood implicitly fuse into the politics of race. So when Bruce complains about a burger in a fast food restaurant, when he insists on a recompense of two free banana milkshakes and a lager, all the odds are stacked up in his favour. Which black manager is going to argue with a bullying white man in a white, bullying state?

Donald is too good a writer ever to put a thought like that in the text itself, though it arises naturally from it. Apartheid is just one of the many lacunae readers have to fill in for themselves – along with the reason for his mother's depression, the substance of her conversations with her best friend in Durban, where she takes her two sons on a holiday to get away from her husband, or the cause of the ever widening splits in her marriage to Bruce. Skilfully, in Alex's own words, Donald shows us precisely what his 12-year-old protagonist can't yet understand.

The novel, he insists, isn't remotely autobiographical. His father isn't at all like the repulsively fascinating, grossly egotistical Bruce. His parents may have divorced, but the cause of their separation was nothing like that given in the novel. His own South African childhood was altogether more boring and less traumatic than the one he invents for Alex and his younger brother Kevin.

He's 35 now, but from the time he and his family left Dundee when he was two, to when they returned there 14 years later – just days after Nelson Mandela was freed – he lived in Pretoria. Try as he did to write about other things, the short stories he started after finishing his degree in philosophy and English at St Andrews all circled back to the country of his childhood. But the version he shows us isn't anything like the South Africa we read about in the 1980s. Anyone looking for the most blatant excrescences of apartheid (the slums of Soweto, the shootings, the deaths in custody, state terror etc) will look in vain. This is a South Africa superficially at peace with itself, apparently untroubled by politics: a child could grow up there and not realise there was anything wrong with it, just as he could fail to realise the relentless decay of his parents' marriage.

"What I wanted to do was to write about a childhood in South Africa as though it was the most normal thing in the world," he explains. And as we talk, in the Ibrox flat he lives in with his wife, just three blocks away from Cardonald College, where he has a part-time job teaching English to (mainly) immigrants, the book's wider aims come into focus.

He's still got a vestigial South African accent, modulated into Scots. Even though it was never the harsh, clipped English of Afrikaans-speakers, it was still strong when he arrived back in Dundee. "I experienced quite a lot of racial abuse because we were from South Africa," he recalls. "My sister and brothers had these funny accents and we were picked on for being racists."

He didn't feel he was a racist – if he was, he was nowhere near as blatant as those Scots in T-shirts that said "Keep Scotland Clean – Throw Your Rubbish in England." "Because that's where racism starts – in something that might sound as though it's a joke or not worth making a big deal of. All these seeds create a 'Them' and 'Us' divide. Imagine if I went round with a T-shirt saying 'Keep Johannesburg clean – throw your rubbish in Soweto.' " It's this nuanced divisiveness – like the antagonism between white Afrikaaners and white Europeans – that features as much in Choke Chain as the more cataclysmic split between whites and blacks.

"Growing up in Pretoria, I felt the inter-white tensions with the Boers far more. Blacks outnumber whites in South Africa by ten to one, but I hardly saw any of them – no more than I would see many black people in Glasgow. Yet at school I would get picked on by the bigger boys from the Afrikaans school. From the outside, you just assume that the only racism was between whites and blacks, but within each group there are all these little divisions. It's all racism, all bigotry, all the same."

Although all of these tensions are present in Choke Chain, they're hardly centre stage. They flit in and out of the main story – the breakdown of Alex's parents' marriage from an uncomprehending child's perspective – from the margins. And when they disappear again, the picture of South Africa that remains verges on the paradisal.

"My childhood was fantastic," Donald says. "We lived in a country with one of the highest standards of living in the world. Even working- class families – my dad was a supermarket manager, my mother a teacher – had two cars, a nice house, a servant, green lawns. Of course, that was just if you were white, and that sits awkwardly with me now, because in a sense I was complicit, even though I was a child.

"But what a lot of people here don't realise is how little of the struggle against apartheid was reported in South Africa itself. There was this big rally in Dundee after I'd arrived back in the city and people were saying all these terrible things were happening, that people were being killed and so on. I got in touch with my friends back in Pretoria and they asked me what on earth I was talking about. Because from a comfortable, white suburban perspective, they just didn't know."

On any narrow definition of politics, Choke Chain is similarly unknowing. On a definition that takes politics as being about the way we treat each other and how we bring up children, however, it is a novel of subtle intelligence with a full house of fully gelled characters and an explosive climax that just stays on the right side of plausibility.

Donald's next novel will move away from South Africa, but still, he hints, draw on his own life as an immigrant and a teacher. "It will have Scots people in it, as well as Afghans and Somalis," he says, "Like them, I know what it is like to come to this country for the first time and experience racism, weird food, dark skies and a completely different culture. I'd like to write about that!"

On all the evidence here, it will be well worth the wait.

• Choke Chain, by Jason Donald, is published this week by Jonathan Cape, priced 12.99. Donald and Janice Galloway discuss writing about families in memoir and fiction at the Bank of Scotland Aye Write! book festival at Glasgow's Mitchell Library, 10 March, 6pm.