The sun's going to shine, dad's going to be with us all the time, the kids are going to be in heaven, it's going to be...hell!
When Tolstoy declared that every unhappy family is unhappy in its own way, he clearly wasn't talking about family holidays; these, at least, display striking similarities in the ways we all make each other miserable.

What endure in the mind are not so much golden days on the beach, as those moments of pure exasperation and despair: hurtling down the autoroute with the radio on full, fingers in ears, singing at the top of your voice to drown out a screaming baby hell-bent on breast-feeding across France; ripping up your only road map during a major navigational dispute with your partner; seriously considering abandoning your offspring on the sands after yet another day of disputes about spades and ice-cream. The ingredients of a typical summer vacation are as familiar as rainy days in June.

What makes it all so much worse is how much we look forward to each holiday as a release from work pressures and a chance to reacquaint ourselves with those we hold dear. But such high expectations put added pressure on already strained nerves, believes Sabine Buckley, an electronic publisher, who goes away twice a year with her husband, Russell, and children, Robin, five, and Francesca, two.

"You leave with all the good intentions, but after a three-day honeymoon you've run out of them all. Spending all your time together, the kids get bored with you and you get bored with them; everyone ends up moaning all the time. It takes at least a week for everything to settle down."

Working parents, unfortunately, are caught in a double bind: they are desperately in need of a rest themselves, but are driven by guilt to spend "quality time" with their children. "We tried Club Med once, where there is plenty for the kids to do," says Sabine, "but because I feel I don't see enough of them anyway, on holiday I feel under more pressure to spend all my time with them. The trouble is then, you never get any time to yourself."

According to Dr Richard Woolfson, a family psychologist, Sabine's experience is typical. As many children and adults have their own lives and don't normally spend much time together, they find it difficult to sustain two weeks solely in each other's company. It's a volatile situation and the flashpoint is often clashes of interests, he says.

"The 10-year-old wants a game of football, Dad wants to read the paper and Mum wants to go shopping. At home everyone can do their own thing, but on holiday, especially abroad, you're more restricted. That's when the children start moaning that they're bored, their parents go off their heads, and everyone ends up screaming."

Even adults must adjust to each other. In household mode, life after work is filled with cooking, shopping, cleaning, getting the car fixed; we don't spend every hour solidly with our partners. "It's about getting used to your partner in a freer situation," says Dr Woolfson, "but that can be difficult. Sometimes I used to feel I couldn't wait to get back to work for a break."

Anna, 41, recalls a holiday in Madeira when she and her partner, John, spent hours arguing every evening about where they were going to eat. He wanted to dive into the first restaurant they came to; she wanted to check them all out before picking the best.

"One night we sat down to order. He wasn't speaking to me, and just picked something from the blackboard. I looked it up, and started to tell him, but he just told me to shut up." Ten minutes later John was staring into a plateful of limpets. "It was then we realised it couldn't go on. From then on we took turns in choosing where to eat."

Unfortunately, other situations are less easily resolved. Like oil and water, small children and long journeys simply don't mix. The problem is that, as with childbirth, we tend to forget just how awful its all been. It's not until you're 10 minutes down the road and the cry comes from the back seat, "Are we nearly there?", shortly followed by "I think I'm going to be sick", that you remember resolving last time never, ever, to do this again.

But equally fraught can be keeping kids happy once you've arrived. Sabine's recent solution was to share a south Devon cottage with two other families - a total of six children between 14 months and six years. "It worked brilliantly," she says, "The kids entertained each other, which took the pressure off the parents, and we got some adult conversation."

But, as Sabine points out, you need to have clear ground rules and agree on exactly what you want. Jane and Bill found that playing happy families with their friends in a remote Portuguese villa backfired from the beginning, even though their two daughters were close friends with the other couple's little girl.

"We didn't have enough toys to go round, so they squabbled constantly and we spent the whole time trying to keep them from each other's throats," says Jane. "While ours went to bed and got up early, theirs was up till 11pm and sleeping in every morning. And discipline was an absolute minefield; you quickly realise that you don't have the same values or ideas about child-rearing. It was a pounds 1,500 disaster; I came back thinking that even if the holiday had been free, I wouldn't have gone."

More cautious couples may never risk a friendship by such prolonged, close proximity, but families are basically stuck with each other. However, there are ways you can take the sting out of those summer weeks, says Dr Woolfson. Prepare the ground; involve everyone in planning and discussing the holiday. This doesn't mean that you should let the children pick the destination (which could mean you'll never go anywhere but Disneyland) but get them feeling involved by talking about where you're going and what you would like to do.

He also suggests a few practice runs. Families who rarely get out of the house for shared activities should limber up for that two-week marathon with a few day trips beforehand. And don't forget to take some time off before you go.

"I take a long time to unwind on holiday," says Dr Woolfson. "In the past I'd work right up to the last minute, then grab my passport and run. I'd spend the first four to five days too keyed up to enjoy them. Now I deliberately take time off before we leave, or book our departure for Monday so I've got the weekend to relax."

Mind you, even psychologists don't always get it right. Dr Woolfson recalls the time he urged his five-year-old daughter to have as much breakfast as she could before embarking on a non-stop bus ride from Tel Aviv to Jerusalem.

"It's a very hilly ride to Jerusalem, and inevitably she threw up the gallon of orange juice she'd drunk for breakfast. As it shot down to the front of the coach, all the passengers lifted their legs in perfect synchronicity.

"For the 20 minutes until we arrived, there were these perfect Mexican waves of feet as the juice hurtled up and down the bus. Moments like that, you never forget"n

Further reading from Virgin Net

British Activity Holiday Association

If you're not sure where to go with the nippers, or what to do when you get there, you can find out here. Links to all kinds of adventurous holidays - from abseiling to windsurfing - with the emphasis on families.

Disney's Family.Com

Excellent one-stop shop for advice and information from Disney. It has a strong American focus, but head for advice-travel for a comprehensive collection of articles on travelling with kids, and don't miss the superb selection of games to play on the move.

The Family Stress test 93q2/stressq.html

If things aren't going well, you might want to see how your holiday rates in the stress stakes. A dozen simple questions and you'll soon know whether you need...

Divorce Online

The last resort after the holiday from hell. The in-depth online guide to breaking up, with useful tips about dealing with the financial and psychological repercussions - and how to get the kids through divorce with the minimum of trauma. Lets hope you don't need to know.

The Independent Online news/independent/index.html

The definitive newspaper on the Internet, with all the latest news, sport and entertainment.