Well, what d'you know? This weekend is National Nude Weekend in California, two days during which the proselytising naturist community will try to persuade the rest of us to loosen up and spend a little time buck naked in the company of strangers.

I am not opposed to nude swimming, sunbathing and the like, but I find the thought of an organised event by people who actually classify themselves as "naturists" wholly unappealing. Richard and Marie are naturists who have agreed to be photographed for a newspaper. She is wearing a hat and it looks like she has on a necklace, too. He is also wearing a hat and a large watch. They are naked and accessorised. It's a self-conscious kind of nudity which reveals the truth: naturists are just the sort of people you don't really want to be naked with.

Nevertheless, all summer long Bay Area nudists have been pioneering "free beaches". Battles with the authorities have been won and lost. Overall, gains include three new nudist beaches on the San Lorenzo River off Highway 9. And Summerland, down south, has also been taken by the nudists. Losses include Kirby Cove near smart Sausolito, where rangers have been telling people to cover up all season. And Baker Beach, which is slap bang in the middle of the city has been threatened by Mayor Brown's declared intention to allow empty housing in the Presidio, which overlooks the beach, to be used by homeless people. It seems they have no more wish to gaze upon the unclad than anybody else.

California's climate of old-world prudery combined with new-age liberalism means efforts to colonise new beaches require astute political acumen to avoid being spotted by rangers. Bob, a dedicated disciple of disrobing explains: "We try to encourage women to take off their tops first because fewer people object to breasts." This smacks to me of the Larry Flynt school of free thought, but female naturists seemed unperturbed by the possibility of exploitation.

Shortly after receiving this particular piece of news, I witness the very phenomenon at work on a (clothing obligatory) beach. Someone 200 yards away removes her bikini top and, suddenly, a wave of women are joining in, unhooking their bras and marching bare-breasted down to the water, accompanied by a frenzy of shouts and whoops. As more and more women join the fray, a woman next to me throws me a sharp look of panic. In the second our eyes meet we reach a bilateral accord and when it's our turn the momentum stops dead.

A short while later, still feeling a little ashamed at being the spoilsport, I check out the woman who set the whole thing off. She's sitting on the beach with a bemused expression on her face and a baby at her nipple. She had only taken her top off to breastfeed. But no-one, bathing beauties included, has noticed. In a country where some women have had to go to court to establish their right to feed their children in public, that's a battle the naturists would be better taking on.