Walking the spaniel on Tooting Common, I was apprehended by a man on a bike. He was ashen-faced. His young daughter, pedalling behind him, had tears streaming down her face. ‘We’ve been attacked!’ he said. ‘My daughter…they set a dog on her…she’s been bitten.’

I looked ahead up the track…et voilà. Once a year, the caravans appear on Tooting Common. There were about seven this time. The usual kids and dogs were milling about. The child didn’t look injured and had probably just been nipped round the ankles. The dog the father was complaining about was a small yappy thing. All the same. They were shaken up. ‘Oh, dear,’ I told him. ‘They come every year. But they usually leave after a few days. They’ll be gone soon.’

‘But I’ve just moved to this area,’ said the man, who was wearing the latest regulation cycling helmet and hi-viz vest and was clearly the sort who did everything a father could be expected to do to ensure the safety and security of his family. ‘I don’t want to live here if this is the sort of chaos that goes on. It’s anarchy,’ he declared, as he pedalled off. ‘Anarchy!’

Thinking this a bit OTT, I wandered further on and as we got nearer the caravans a scrappy Jack Russell attempted to involve the spaniel in carnal relations. I had to beat it off with the dog lead I was carrying. Suddenly a crowd of kids approached, one riding a tiny pony.

‘Give us yer dog, Miss,’ said the pony boy.

‘Where d’ya get that whistle. I wanna whistle like that,’ said another.

‘Don’t you think that pony is a bit small for you?’ I asked, suddenly taken by the idea that I wanted to talk to them.

The children laughed, as if what I had said was quite witty. ‘Go on! Let us have a blow on yer whistle.’

‘This whistle was so hard to get hold of, you have no idea. I went everywhere.’ And I found myself telling the children my troubles and having quite a jolly time.

Then one of them pointed at Cydney and said, with a sharp tone: ‘Your dog just did something. Clean your mess up.’ I looked back at the fly-tipped heaps of trash by the caravans, the branches broken off oak trees for campfires, the nappies strewn on the ground. ‘You’re telling me to clean my mess up?’

And all of a sudden the atmosphere wasn’t very friendly at all. The children laughed. The boy slapped the pony round the neck and made it run, his feet dragging on the ground.

They followed me all the way to the playground, or ‘natural play space’, and burst into it with the pony, sending all the middle-class families running for the hills. Then they got bored and spilled back out again. At which point, an old friend turned the corner and shouted hello to me. As he approached and saw the children, he stopped. ‘Bloody hell, where have all these p…’

In slow motion, I saw him beginning to pronounce the word. ‘NO!’ I said, trying to stop him. ‘Noooooooooooo!’

‘…ikeys come from?’

And the kids magically stopped screaming and went quiet at once. ‘What did you say, mister?’ said pony boy.

‘Nothing,’ I shouted. ‘He didn’t say anything.’

‘Yes, he did. He said pikey.’

We were pinned against a hedge now.

‘Calling us pikeys is like calling a black person a nigger,’ said pony boy. ‘We’re gonna call the police.’

I decided attack was the best form of defence. ‘Well, how about that poor mixed-race child on the bike that you set your dog on. Hmm? Maybe the police would like to hear about that.’ And I picked up my mobile phone and dialled 101. Naturally, it took minutes for them to answer.

‘You can’t be calling the police if it’s taking that long,’ said pony boy, who was obviously used to a speedier service from the Met.

Finally, they did answer and asked me what the problem was. The problem was my vocabulary now completely deserted me. I couldn’t remember the only permitted word in the English language to describe the people in caravans.

So I said: ‘There are people, er, people on Tooting Common.’

‘What people?’

‘People. In caravans. You know.’

‘No, madam. You’re going to have to describe what people you mean.’

‘Er, people in caravans with lots of children. And dogs that haven’t had the snip. And the children have muddy faces and are riding little ponies. They happen to be Irish, but I’m sure that’s a coincidence, they could just as easily not have been Irish, I’m not making any kind of racial point…’

The police gave me short shrift. But at least I didn’t get myself arrested.