MRS P H of Fife (The Traveller, 24 July) said she was planning a family holiday in France with friends. 'I find the whole thing a bit daunting: can anybody provide reassurance that it won't turn out to be a nightmare?' she pleaded.

'If Mrs P H has any cracks in her marriage, or frequently finds her own children fairly intolerable, she must not consider a holiday with others,' writes Mrs Lynn Rylands of Maidstone, Kent.

Mrs Rylands goes on to offer a stack of advice based on 20 years of holidays with friends - with and without children. 'The property must have one bathroom per family when offspring are included. Toss up for bedrooms and make the best of them. It is enjoyable for all if catering and washing up are alternated between families nightly. Those who cook must also wash up on the same evening.

'The shopping kitty must be worked out on a per head basis. Eating out should be settled separately. Excursions always seem to be amicably arranged, particularly if two cars are available. It is very therapeutic to have separate days out occasionally when grievances (about the other family) can be aired loudly and privately.'

Then comes Mrs Rylands's killer tip, the anguish behind which would put anybody off the idea of holidaying with another family forever: 'Prepare yourselves for the Big Bust-up that occurs without fail about halfway through the holiday. This may come through some child-induced irritation (the other family's child, of course]) or some inconceivably selfish adult behaviour - on their behalf, naturally. Our family has a long list of the insensitivities of our co-holidayers - we haven't seen theirs because we, of course, are so accommodating]'

Mrs Rylands, who sounds like the perfect companion for any co- holiday, says that while there are rows, they are quickly forgotten (by the end of the year, at least). 'Come Christmas - or at worst by next summer - we have all been ready to laugh over fondly remembered outings, meals, etc, barely dwelling on the days when the rice was thrown at the wall, or when the chocolate yoghurts were all eaten at a private sitting by one child, to the blind fury of everyone except the doting mother. This last one, believe it or not, was the worst and nearly the acrimonious end of several years' harmonious friendship and a marriage.

'Good luck, Mrs P H - you could have the best holiday you have ever had.'

Or she could spend the fortnight scraping rice off the wall and gulping down tranquillisers in the privacy of a darkened room.

There is little comfort, either, from Pauline Hukin, of Cleveland. 'Food, drink and lavatorial proclivities are the main pitfalls. A kitty tends to cause an outbreak of uncharacteristic meanness, with someone feeling done because someone else has drunk more wine than they have, or has not left enough milk to go round.

'Your own children's eating habits are bad enough, but it's a dead cert that the other children will have outlandish diets (chocolate spread on garlic bread for breakfast), will go 'Yuk' at whatever you prepare for them, and be allowed Coke all the time. On no account let anybody except your nearest and dearest get their hands on the Heinz salad cream - you can't buy it in Leclerc.'

Mrs Hukin says that eating together is fine as long as it is structured as it is at home, with 'your own etiquette not infringing on the others'. After a few days, it's easy to become obsessed by the way the husband swills liquids around his mouth before swallowing.'

The most attractive solution, concludes Mrs Hukin, is for one family to take charge of both sets of children for one week's purgatory in the gite, while the other couple go elsewhere and pamper themselves. 'Failing that, phone up a mutual friend back home on about the fifth day and offload all your frustrations. Then go and share the salad cream]'

Shared family holidays sound a great source of material for our 'Wish you weren't here . . . ?' postbag. Your tale should be brief - not more than 200 words - and can be about anything to do with travel. Please write to: Frank Barrett, 'Wish you weren't here . . . ?', the Independent, 40 City Road, London EC1Y 2DB: a special travel book for our weekly winner.