Four years on from Anne Cantelo's divorce, four years in which she and her ex-husband made Herculean efforts not to allow their broken relationship to compromise their parenting, the younger of Cantelo's two daughters, Gabriella, came home from school and said she had spent her lunch hour comforting a friend whose parents were splitting up. Asked what she said to her friend, Gabriella replied: "That it's no big deal, really."

Cantelo was delighted. "If she had known how much I'd been beating myself up..." she says. She realised in that moment that her efforts had paid off - the children were fine.

Gabriella's words are now the title of Cantelo's first book, a parent's guide to making divorce easy for children. In it, she stresses that family break-up need not lead children to suffer lasting consequences, either educationally or emotionally. Dare she say it, it can even have positive outcomes.

That is wildly at odds with the popular perception that is widely repeated: that children of divorcees are more likely than other children to fare badly at school, get into alcohol and drugs, and commit crime. Advice books, as Cantelo herself found, tend to focus on dealing with the problems, not preventing them. The self-evident truth - that many children of divorced parents go on to be professionally successful and have long, happy relationships - tends to be regarded as some sort of fluke.

But that is simply not the case, says Cantelo: divorcing parents, with good intentions, the right advice and a measure of self-discipline, can have an amicable divorce that allows their children to go on feeling safe and secure, knowing that they are loved as much as ever by both their mum and dad.

Cantelo's book draws on her own experience, that of dozens of parents and children of all ages who have been through family break-up and the help of Gill Jardine, a psychologist working with the children of divorcing parents. Cantelo is hesitant about presenting her own family as a model of success, acknowledging that she and her ex made mistakes and that there were times her daughters must have felt as if their worlds were "caving in". But, as she points out, it's a rare person who gets through their entire childhood without experiencing some sadness or trauma. "We did get through it," she says. "The message is: divorce doesn't have to be a disaster."

Nearly all divorcing couples start out intending to do things amicably. But Cantelo quickly realised that many were simply not prepared for how suddenly a hitherto good-humoured situation could turn bad and how their behaviour towards each other would affect their children. "What struck me was that people who behaved the way my ex and I did, their children were fine, but those who made more mistakes, their children suffered more. That cause and effect was quite clear."

She acknowledges that her ex-husband is "mature and responsible", which has helped, but rejects the idea that she was simply "lucky", arguing that most men would be as reasonable as her ex if not demonised.

She identifies demonising of the ex-partner as one of the most common mistakes people make. "Even your friends will encourage it," she says. "You have to stop that right away." Nor does she mince her words about divorce lawyers whom she regards, with a few honourable exceptions, as a generally malign influence. "Almost every instance of where a divorce got really nasty is where lawyers got involved," she says firmly. She did not spend anything on a lawyer.

It's probably clear by now that Cantelo is not in the business of giving unconditional commiseration. She understands fully the anger that comes with divorce, but her message is uncompromising: no parent should allow their own feelings of hurt, however strong, to undermine their children's relationship with the other parent. She warns from the outset that some of her advice might make people throw the book at the wall in irritation, but adds: "Many of the people I spoke to bitterly regret things they did that seemed fairly innocuous at the time but in hindsight were plain stupid (their words) and had a devastating long-term impact."

Others, by contrast, like the Duke and Duchess of York, handle things very well. In fact, she believes a well-managed divorce can be a good thing, leading children to be "warmer individuals who are closer to their parents".

Here are a few words of advice from Anne Cantelo on how to minimise the upset caused by divorce.

Should you try to stay together?
Consider carefully whether marital problems such as boredom, unfair division of housework or constant criticism could be put right with communication and commitment from both sides.

Be prepared for tears, but don't encourage them
"Telling someone you don't love them any more and seeing their face collapse into grief is the toughest thing most people ever have to do; that is until you have to sit your children down and tell them you're going to rip their life in two."

The moment divorcing parents tell the children needs careful forethought. Don't: tell them until you're certain it's permanent; do it in front of anyone else; try to defend your decision; leave your spouse to handle it alone; suggest you blame the child in any way. Do: be prepared for them to cry, but don't encourage it if they don't; try to tell each child individually; reassure them of your love and that you'll both keep on seeing them; promise them that you'll stay as friendly with one another as possible; be as honest as you can.

Don't assume older children can cope better
Often the opposite is true. Cantelo found that people in their 20s and 30s whose parents were divorcing could be deeply upset for years afterwards.

Try not to involve a lawyer
Good lawyers will encourage you to have mediation; bad lawyers will make things worse. One woman Cantelo spoke to spent £20,000 in legal fees - over a coffee table. That's extreme, but, she warns: "Amicable divorces can be made acrimonious by just one visit to a bad lawyer." You may want a no-blame divorce, but a lawyer may encourage you to go for an earlier settlement by citing unreasonable behaviour: if you do, your spouse may cross petition against you and the whole thing could spiral out of control.

It isn't always possible, of course, but she advises going for a no-fault, DIY divorce, which involves filling in a form, for the cost of an expensive meal for two. You won't be sure that you're getting everything you're entitled to, but, she says, so what? You will have more money left between you to provide two homes for the children. Courts often aim to maximise the living standards in the primary carer's home, with the other parent consigned to a cramped flat or bedsit. Is this the best outcome for the child? Perhaps one of you will have to downsize so the other can provide a better environment for the children. Clearly, less well-off couples will struggle to provide two comfortable homes for the children, however amicable the divorce. Still, the less acrimony, the better.

You can get a separation agreement to ensure the division of your assets is enforceable - finalise the details between yourselves and simply get a lawyer to witness it.

Don't bad-mouth your partner to the kids
Having divided loyalties is traumatic for a child. No parent should make negative remarks, however veiled, about the other parent. On matters of discipline, stay united: back up your ex or, where you disagree with something they've done, discuss it privately. Most of all, Cantelo says, don't try to push them out of the children's lives, no matter how you feel about them - your children have a right to both their parents and will eventually resent you for pushing their other parent away (clearly, in cases of abuse, this does not apply - the child needs to be protected from the abuser).

Don't be afraid to show you're grieving
Otherwise, your children could grow up thinking it's good to bottle up their feelings.

Don't confide in a gossip
The ideal confidant is someone who listens but does not encourage you to demonise your ex. Pick one or two friends who are clearly more yours than your partner's.