We found the perfect vantage point. It was just after the pelican crossing on the high road, on a bend. Vehicles in the show would be forced to slow down at our exact spot. We shuffled among the all-terrain buggies and waited for something to happen. To pass the time, I described to Alexandra what carnivals are like.

"Well, there will be girls dressed up like princesses. Loud music to dance to, costumes in bright colours. Lots of children jumping and leaping, balloons probably . . ."

"Why?" she asked, with the pure logic of childhood. My first thought was: "No idea. For the hell of it . . ." But parents are the best bullshitters. We never, ever say "don't know" to our children. Better to pretend some obscure knowledge of ancient history than sound thick in front of our prodigies. A girl called Charlotte was asking her daddy (he had Armani sunglasses on despite the clouds) the same question. He came out with the identical rubbish I'd had on the tip of my tongue.

"Well. Summer carnivals and the like were once pagan festivals. In ancient days, the tribes of this land would . . . er . . . light bonfires several times a year. They'd probably make carvings and jewellery to sell or exchange, too. The main thing was to gather and give thanks to the sun for shining and making their crops grow."

"But the sun's not shining today, Daddy."

The leaflet stuck to the lamp-post behind us read "Carnival at 2.30pm, Saturday". No reason was given except that it was "summer" and this was a "summer parade". The word "procession" was there, too, just to confuse matters.

Then came the first "boom bah!" of a big bass drum.

A skinny girl of about 13 twirled a baton uncertainly. Twice to the left, twist, twice to the right, pause and repeat. She was desperately counting under her breath. Behind her meandered a troupe of majorettes. The cultural reach of the US is never far from the high street. Parental jaws dropped in unison at the first sight of our "entertainment". Somewhere in the distance I could hear Alex clapping and cheering: "Look, Mummy, the girls are in shorts and bik-i-nis." We all stared, goggle-eyed, at 15 wobbling, hobbling, pallid, pre-teen girls, squeezed into sequinned hot pants and microtops. One girl of about eight was so fat that four rolls of flesh sweated and chafed publicly above her shorts. She looked like Bernard Manning's love child. The poor kid tried to skip to the left and then to the right with the others, but could barely pick her feet up. What we watched was a stumble to one side and an immense effort to stay standing, followed by a token fling of her left arm.

The procession had come about 800 metres by the time it reached our bend. The girls looked as if they'd been to Everest and back. Mini Manning wasn't alone. Over 70 per cent of the miserable, humiliated girls looked like classic couch potatoes, pasty and glassy-eyed.

This antithesis of a carnival staggered on. Three more lumpen groups in skimpy Spandex stumbled wearily past. Hatchet-faced mums stalked slowly alongside. "Get in f***in' line, Mandy," yelled one, grabbing a baby whale by the arm and propelling her back into the line-up. This is raising money for charity, I reminded myself, as a little boy in a flower-covered Ford Escort flicked two fingers up at Alex.

Finally came the "Carnival Queens", who were a little easier on the eye. Pairs of girls in heavy make-up and white dresses wafted their hands at us as if we were spoiling their fun by looking at them. "Is this a carnival?" asked Alex after the third float of bored teenage girls had sneered its way past. For the first time in her brief life I had to concede, "I don't know what this is." And I was tempted to tell her: "This is a festival for the fast-food giants, a celebration of the hydrogenated-fat lifestyle."