Yes, if I knew a child was being abused, I would take things into my own hands.

A two-year-old boy was dead, his mother charged with his murder.

It was not the first time I’d seen this kind of tragic story on the television news. But I kept thinking about this particular little boy because the reporter detailed how some of the boy’s neighbours had reported the family to community services a number of times, as had family-day-care staff who’d seen bruises and bites on his body.

One of the neighbours was interviewed and said that everyone in the neighbourhood had been worried about the toddler because he didn’t ‘look right’.

Later that night, lying in bed, my three-year-old daughter sleeping in the next room, I couldn’t stop thinking about those women – the neighbours and the carers – who’d tried going through formal channels to get that little boy help. But help did not come, or not enough of it to save him.

I wondered what I would do if I knew that the child next door was being abused. I’d certainly notify community services, but what if no help came, and I was worried the child would be killed?

Would I take things into my own hands?

These are the questions that prompted me to write my novel, PROMISE, in which a woman realises that the five-year-old girl next door is being badly abused. When community services don’t respond to her reports, she takes the child and runs.

Too often, the government bodies set up to protect at-risk children are only able to respond to the most urgent cases. Someone who works in this field and who I met in the course of researching the novel told me that he knew of child who hadn’t been visited by community services after seventeen reports of concern.

In the case of the two-year-old boy, child protection case workers walked off the job soon after his death, protesting a long-term lack of resources which meant they’d been unable to follow up reports that he was at risk.

Undoubtedly, government funding to support victims of all forms of family violence should be increased – something that 2015 Australian of the Year, Rosie Batty, has been very vocal about.

But what of our individual responsibility to the children around us? The children in our street. The kids we pass in the supermarket aisle. The child we see at the park sometimes.

It’s easy to turn a blind eye when we suspect a child may be in trouble. I’ve done it. I’ve walked by someone smacking their child in the supermarket. I turned away because it felt intrusive and – to be honest – because I didn’t want to get involved. Most of all, though, I didn’t know what to do.

That uncertainty was paralysing: What if I made things worse for the child? What if there was a risk of being harmed myself?

Last summer, my partner, Alan, and our young daughter parked outside the local swimming pool, ready for a game of Marco Polo in the kids’ pool. Then, near the car park, they walked straight into a situation where a man was verbally and physically assaulting a woman and a boy of about ten. Alan ran to the pool entrance, our daughter in his arms, and asked them to phone the police. Alan was afraid of the man and worried for our daughter, but went back out to the footpath and called to the woman and boy, "Come in here, come in. You’ll be safe in here."

And someone at the pool said, "No. He can't come in here. That would be too dangerous."

I understand that the person who said this was concerned about the man bringing his unpredictable violence into the pool complex, where staff had a duty of care to patrons. But I also wanted to cry to hear that the local pool – filled with people on a sunny day, people from this woman and boy’s community – could not be a refuge for them. This exchange only added to my questions about how far our circle of responsibility reaches.

As it turned out, the woman and boy didn’t try to come into the pool, and thankfully the police soon turned up, and the last thing Alan saw was the man being bundled into the back of a police wagon.

That kind of family violence is at one end of the spectrum; at the other end is the exhausted, overwhelmed parent losing it in the supermarket and screaming at or smacking their child.

I understand how those supermarket meltdowns happen; all parents lose it at some point, whether it happens in the supermarket or behind closed doors. Because parenting can be hard. And harder still if you add exhaustion, financial pressures, ill health and stress to the picture.

I can’t imagine anyone suggesting that it was wrong to call the police in relation to the incident outside the pool. But is it right to step in when a parent is screaming at or smacking their child in the supermarket? If so, what do we do? What do we say?

And what do we do if we suspect someone is hitting or sexually abusing their child, behind closed doors?

While researching and writing my novel I have – for the first time in my life – thought a great deal about these questions, and I now know that I will do something (and – despite what Anna, my character, does – I’m not contemplating abducting a child).

I think my conviction to do something has been heightened since becoming a mother, perhaps simply because a child’s profound vulnerability and sensitivity has been right under my nose, day in, day out, and I’ve rubbed right up against that notion – so socially entrenched – that parents somehow own their children.

I remind myself that this is the first generation to question the parents’ right to hit kids. Alan was caned often at school, and I remember my brothers being smacked on the back of the legs with a wooden spoon.

The next time I see or suspect a child is being abused, I hope I will push past any sense of paralysis, and call the cops or the Child Protection Helpline. Or befriend the kid. Or offer support to a parent who seems overwhelmed, because I know when a parent is overwhelmed their reserves of patience are tested. I hope that I’ll approach the mother screaming at her kid in the supermarket and say something like, "Can I help? You look like you’re having a hard day." And I know I’ll keep sending letters to politicians about funding.

Writing PROMISE has been pretty hard going at times – even with my determination for it to be ultimately uplifting – but it’s been powerful in helping me clarify my own values and thinking, and has left me knowing that I will act to protect children, even if it means stepping way out of my comfort zone.

‘Sarah Armstrong’s new book, Promise is published by Macmillan Australia. For more details see Pan Macmillan Australia.