On Sunday May 15 the RSPCA held its 23rd annual Million Paws Walk, which raised a bunch of cash for unloved mutts. It’s a noble cause but when Jeremy Chunn went along a few years ago he found that with thousands of well-fed dogs, the scene soon turns ugly.

The Royal Society for the Prevention of Cruelty to Animals fights for the four-legged and impoverished, the voiceless and dirty, the kicked-about and wild-eyed. It’s an endless task. And they don’t have enough money. But dog-lovers are an evangelical subspecies of humankind and somehow the RSPCA can tune these people to act as disciples for their cause.

That’s how a dog-hater can be convinced to pay $30 to walk four kilometres in a public park with his two kids among bushy-haired animals who won’t ever end up in the organisation’s cages at Yagoona, and their passionate, look-alike owners.

The dog people arrive early and park their shampooed cars in the high-revenue spots of an otherwise totally empty Homebush Olympic Park. It’s a nice sunny day and all the animals have had their bowels tightly packed at breakfast. We queue through a starting gate, show our registration papers and then are launched v-e-r-y s-l-o-w-l-y into a thick column of humanity and Canis lupus familiaris.

Very soon we see our first collision of what look like wholemeal bread rolls. The turds are large and almost humanoid. We say little and move on.

The next heap is darker, smeared at one end, but also very large. My dog-loving friend expresses her disappointment. “Oh dear,” she says. “Someone should have picked that up.”

We detour the animal waste and move on, among sheep dogs, dachshunds, terriers, a great dane, those bull-nosed aggro ones that eat people’s limbs, a few miniature dobermans who should be put to sleep before they get any bigger, whippets, lots of those white little ones that always have their tongues sticking out, a huge black thing that was dribbling a white rope of saliva, something that looked like a small horse but which was a dog and various other forms of furry barrel.

Slowly we arrived at a grassy area to be handed water bottles and hand sanitiser by RSPCA volunteers as the leashed beasts sprang into scalloped kids’ playtubs of water that quickly turned brown. Around us could be seen small piles of faecal matter.

We pressed on. With only a kay to go, long coloured skids told of more “accidents”. All dog-owners surely know you can’t pick up a smear and put it into a little plastic bag. Oh no. “Ooops! Sorry, mate. I was just about to pick that up. Sorry about your… open-toed shoes…”

My son stopped to let my friend’s dog drink from his bottle. The animal later stopped to peel some poo from the ground and eat it. “You’ll need to boil that bottle when you get home,” she said.

And I did boil his bottle. Twice. And then threw it out. Even the hand sanitiser went in the bin.