Dad of 4, Harry Wallop, takes us through the highs and lows of holidaying with extended family.

Summer holiday. And that means the great gathering of the in-laws. All 21 of them. Or is it 22? I’ve lost count. Yes, we contribute six of that number, but that is nonetheless an awful lot of members of my wife’s family in a small space in a foreign land.

People always look horrified when they discover I voluntarily spend a week of my summer with my wife’s mother, all of her siblings, her siblings’ spouses and their assembled children, and now their assembled children’s girlfriends. I’ve been doing it since we were married, now well over 15 years ago. It started off as an unwieldy group in high single figures, but manageable.

It has now stretched into a caravan of humans, luggage and lost boarding tickets. A group, which requires the size of accommodation demanded by a national football team off to the World Cup. Sadly, we tend to have the budget not of Germany, but of Senegal.

The ages range from 6 to 84. Considering my in-laws’ collection of failed marriages, neuroses, dietary requirements, willingness to compensate for their lack of foreign languages by SPEAKING ENGLISH VERY LOUDLY to Italian waiters, and thirst for a really good row, it is a recipe for a combustible disaster.

For starters, there's the enjoyable game of trying to discover how your mother-in-law has reached her 23kg Easyjet luggage limit for a one-week trip.

But it sort of works. Every year I vow it will be the last, and every year I agree to do it again because the children adore it so much: cousins on tap, sleeping in rooms with four other people, swimming pool Olympics. It’s the closest they’ll ever get to Malory Towers.

And I too get quite a lot in return for putting up with my sister-in-law questioning my parenting on a regular basis (‘Is that computer game really suitable? Should he be drinking that?’).

For starters, there’s the enjoyable game of trying to discover how your mother-in-law has reached her 23kg EasyJet luggage limit for a one-week trip.

The answer is that she has packed: a box of tea bags, washing up tablets, rubber gloves (‘for the kitchen, mind. Don’t you go using them on the loos’), a spare set of sheets (‘just in case’), a hair dryer, enough outfits to dress a touring cast of Les Miserables, and full first aid kit.broad were before the low-cost revolution, have failed to master the art of hand baggage only.

Visiting the local cathedral or travelling to the village café is an exercise in how toddlers and octogenarians both take an intolerable amount of herding.

But the key benefit is the adult-child ratio means that the parents are able to siesta or lie-in, safe in the knowledge that their children are not drowning in the pool. The teenage quotient means the preteens have card players, boulle-sharps and wise crackers to look up. The younger ones are petted like stray cats. No one is bored. There are enough people for a seeded table tennis ladder. You are never short of a Bananagrams group.

The single biggest downside of holidaying with so many people, however, is the cousins’ lemming-like urge to do things in convoy. It’s exhausting. Visiting the local cathedral or travelling to the village café is an exercise in how toddlers and octogenarians both take an intolerable amount of herding.

Each year, I concoct ever more ludicrous plans to shake some of them off. I just want a morning when I don’t have to stand by the front door bellowing: ‘Please, can we get a move on!’ This explains, as each year passes, my ever-more eccentric choices for day trips. Surely, no one will want to join me in visiting the concrete museum or sardine shop. ‘It’ll be really boring,’ I say, ‘but I’ve always been interested in twentieth century building materials.’ But try as I might, most traipse along.

Each year, I concoct ever more ludicrous plans to shake some of them off...surely, no one will want to join me in visiting the concrete museum or sardine shop.

But for all the hassle and occasional row, it’s fun. It’s all part of the joy of being part of a big family. The children learn to share and help out. The grown-ups get some time to read a book. If nothing else, you can return home, smug in the knowledge that your parenting is superior in every way to that of your sister-in-law’s.