You often see those who don’t follow this rule out in public: the unprepared wanderer operating as a feckless innocent, blissfully unaware of the minefield they are creating for themselves. You might even observe them every time you go out. Just venture into a nearby park on a hot, busy day and look around. Sometimes it can make you weep with pity.

Hello! Who is this affable fellow ambling towards us with a sweet child, his gargantuan backpack jangling like a tinker’s caravan and his chest puffed up with paternal pride? See how the apple of his eye gnaws contentedly on an ice-lolly, whilst holding onto Daddy with the non-sticky hand. Dad thinks he has this one cracked.

Yet look closer and note how Affable Dad sniffs suspiciously. Perhaps all is not so well, and a public change is required. `Let’s get you checked you out`, he says with a faux long-suffering sigh and mildly melodramatic roll of the eye whilst an old lady `awws` at him and the infant. Any audience-conscience air of, 'bless the little tear-away (but see how in control I am!)‘ evaporates as the passers-by gag at the smell unleashed from the trousers of the rosy-cheeked sweetheart.

That suspicious paternal sniff from only 90 seconds ago has suddenly been joined by a facial expression involving some kind of nasal contortion, making Dad look like he has just snorted wasabi and is now gagging. We may pity him, but least he seems to be well-stocked.

Well-stocked maybe, as he dops his heavily-loaded packback like a Bactrian camel carting it’s howdah onto the sand.

Indeed, it is now that we start to question this father‘s practicality. Affable Dad, swearing softly to himself, sorts through the spread of items strewn across the grass beside him as he seeks to locate his nose-saving tools. By now, the `awwing` old-lady has retreated a safe distance away and looks grimly on. She has seen it before, for this poor fellow has been sucked into a minefield. His kit is in disarray, he fumbes for wet-wipes, pants-bag, muslins, tissues while one hand rests on the small person who has somehow managed to make the transition from toddling menacingly to being flipped onto his back. Incredibly, the ice-lolly remains in tight grip. Although it is now part-melted, slithering onto the ground and contributing to a screaming tantrum and extra sticky fingers.

Dad, wipe and bag are now rendered completely unsuitable for clearing up the horrific mess that has ruined the day. Such disarray has fed deep humiliation and driven away all nearby park-goers. Meanwhile, the apple of this father‘s eye has all but sealed his ruin by twisting so frantically that the faecally-smeared nappy has started smearing elsewhere. It is a sad, smelly sight.

What if Affable Dad had been better prepared? What if he’d been armed with one easily-navigable nappy bag which could aid de-bagging and re-changing in one smooth go? What if there were easy-to-reach compartments, pouches, flaps, magnetic buttons and wipable fabric? What if this one-handed grizzled parent might reach back and, without looking, pull out the nappy, change the child, and produce a contented companion all in one go?

What’s the solution to this mad-dash, upside-down world of patenting?

It’s obvious; it’s about having the right bag.