Hollow laughter rings out when anyone mentions “empty nest” or “off your hands, then?” knowing that our children are aged from 24 to 31. No, our nest is not empty. No, our hands are not free. Yes, they are all working, and the eldest has moved to Brighton: but we still have one under our roof, and the other two living 500 yards down the street.

None married. None able to afford even a small flat in Crouch End.

Which leaves us, the ageing parents, as hoteliers and landlords to a trio of adults. “How lovely,” is people’s wistful reaction, especially if their own have emigrated, “to have them so near.” But is it lovely? They are in our pockets and under our feet. Their large persons materialise daily, crashing through the front door, filling the hall with their bikes, talking loudly on their mobiles, flinging open the fridge to indulge their still-adolescent appetites, throwing sweaty clothes into the laundry and dashing upstairs for a shower – a long, splashy shower – before crashing out again.

If this sounds like teenage behaviour, remember that the teens have been officially extended to 29 – just as our 50th birthdays are the new 30th (so we shall soon meet our own young in the middle). They eat the prawns you had been saving. They borrow your CDs, use your broadband and car and petrol and wine. At 4am they arrive home, bringing friends to doss in the spare room. At weekends they rise at 1pm. They scrutinise your domestic habits. We overuse the dishwasher, they tell us; we ought to recycle our eggshells. Our front parlour is a “pointless” room, in a “totally inappropriate” style.

But they get furious if you redecorate a room so it no longer resembles the ramshackle old playroom it once was. They tell us the whole place is too big; if they weren’t around, we’d need a lodger. “But I’d love an empty house,” I reply. “I’d love to be able to wander from room to room.” This is only partly true; I only like wandering into rooms that soothe, not assault, the senses. Untidy children’s bedrooms – no, don’t go there, that way madness lies, just shut the door. But the young return from gap-years and uni with far more stuff than their small flats (which never seem to have any cupboards) can store, even if they do move out.

So our nest is still stuffed with their stuff. Every drawer and wardrobe crammed, and belongings overflowing into spare rooms and landings – books, backpacks, trunks, tents, ancient ghetto-blasters and electric kettles and strange statuettes from some gap-year land. I saw a bulging black sack the other day, labelled “Tees I hardly wear”.

I partly blame the size of the house. But I also blame my husband. He would rather have them around, and they turn to him in a crisis. As I write, he is driving Emma (28, a publisher) across London, to where she has locked her bike after leaving her key behind. He is also the family cook, and regards a table of fewer than six people as a sad undernourished thing.

And I need them too, for all kinds of things: to programme and download; to tell me what’s new on the street; to be mocked by me for what they don’t know; to mock me for what I don’t know; above all, for laughter. They are very funny, when they are not enraging.

The answer to “What are children for?” is “to amuse us”. And to do that, I concede, they have to be around.

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