It was Day One of the long summer holidays and I'd volunteered to have two of my five-year-old's pals for the day, to join me and his older siblings. It was also the hottest day of the year, with temperatures in London soaring to 33C.
My mission: to get through it as unscathed as possible, with as little effort as possible. The obvious answer was to head to the opening air swimming pool at our local park. Result!
For two blissful hours, the five kids splashed around without a care in the world, while I read my book, without a care in the world.
The atmosphere was alive with the babbling brook noise of giggling children – the sound of a perfect British summer.
But on the stroke of noon, the mood started to change as the early birds were joined by the late risers.
Laughter was replaced by shouting – or 'SHARRTIN'; splashing was spoiled by dive-bombing; and swearing began to pollute the airwaves.
"Time to leave," I said to my gang.
And they left without protest (and on the promise of ice creams). Their fun had started to feel fearful.
We packed up our towels and made our way out, and as we exited, I saw a group of seven (five girls and two boys) who were all about eight or nine years old – my oldest son's age.
I noticed them because they weren't with adults – but mainly because they were swearing at the tops of their voices.
Then one of the boys lit a cigarette and put it to his lips, before offering it to one of the girls.
"Nothing to do with me," I thought. "They're not my kids."
But then my eight-year-old asked me, 'Why are those kids smoking?' and I felt I had to have a word.
Now I'm not a policeman or a busy-body but like anyone with half a brain cell these days, I know about the dangers of smoking.
But then again, I thought, perhaps children under the age of 10 DON'T know that it causes lung cancer and heart disease, so I felt it pertinent to point this out if for no other's benefit than the charges I was responsible for that day.
So I piped up: "It's not good for you, you know, smoking. Causes cancer and lots of other things."
I didn't tell them it was illegal, or that I would call the police or tell their parents (would that have done any good, even if I had?), I just pointed out the health risks. But the response left me stunned.
The rat-faced child with a suede haircut narrowed his already narrow eyes and curled his lip, then spat: "Mind your own business, you facking cant."
My first thought was, 'Can't' what? But then I realised it was the little demon's accent and what he was calling me was nothing to do with Can or Cannot.
A moment later, his friends began to laugh at what he'd said - and at me.
"Yeah, what's it gotta do wiv you, facking cant?" another smirked.
"Yeah, fack off, fack yerself, facking cant."
They continued to laugh as I stared back at them, shellshocked and speechless.
My son tugged at my sleeve and asked: "What's going on, Dad?"
But before I had time to reply, the smoker chipped in: "Is he your dad? He's a facking cant."
I don't think I've ever felt more disarmed and less potent in my life. I had nowhere to go. I was speechless. If I was to chastise, they'd ridicule me further, and obviously a clip around the ear was out of the question – and the little thugs knew it.
So instead, I turned away, ushered my charges across the road, and pretended to be oblivious to the ongoing onslaught of abuse that was reaching my ears – "Cant. Cant. Facking cant. Yeah, fack you, facking cant" – until we were all out of earshot.
My eight-year-old looked up at me, crestfallen – his Hero Dad had been taken to pieces by a group of kids his own age.
"Why didn't you shout at them, Dad, like you shout at us?" he asked.
And not for the first time that day, I was rendered speechless.
What could I have done differently? Call the police? Social services? What would you have done?
What I do know is that I won't be doing it again.