There was an anti-smoking advertisement which showed an alluring woman puffing away while a horrified male voiceover whined: "It's like kissing an old ashtray." As sexual aversion therapy, this seemed curiously crude. Without wishing to go as far as James Dean, whose rough-trade soubriquet was apparently "The Human Ashtray", I have to confess that the taint of smoke can be positively erotic.

My first experimental drag tasted overwhelmingly of the mouth of a sexy smoking boyfriend, and brought a rush of pleasurable, Proustian associations. Being a non-smoker in a nightshelter for the homeless was to miss out on a powerful symbolic tool. I gave myself 36 hours shut up in a small flat and vowed to learn to smoke.

It didn't help that I'd started with John Player Specials, the Pot Noodle of the cigarette world, but after a few hours of lounging around and posing critically in the mirror - hand flipped up or flopping down, cig pinched between finger and thumb, or dangling casually between index and third finger, sucking seductively a la Bacall or surreptitously like the spiv in Dad's Army - I had progressed to the slow, thick curl of smoke rolling over the upper lip and disappearing into flared nostrils. The next day I emerged, blinking and puffing and practising my new mantras: "Got a match?" and "God, I know I put my cigarettes down here somewhere..."

I thought there would be a few jokes, a few raised eyebrows back at the house, where stained fingers and whiskers were the norm, but no one expressed any surprise. But then, in a nightshelter, no one expresses much surprise at anything: people throwing tantrums, or bricks, or each other downstairs. Cornering a belligerent resident became much easier with the offer of a fag. Smoking was somehow egalitarian; workers who really wanted to go native started rolling their own, though this was largely seen as an irritating affectation by residents, whose plaintive, begging cry was always: "Got any straights?"

According to her biographer, the writer Elizabeth Smart preferred Gauloise, except on "non-smoking" days, when she switched to Marlboro. Attagirl! I was soon up to 30 a day, working my way through the brands, revelling in packaging, the rip and slither of the cellophane wrapper. The smart, dull gold of B&H, comic-strip Camels, Sobranie Black Russians, Kents in the squashy soft packets, St Moritz, packaged for the sophisticated lady.

Six months later I sat in the smoking section of a jumbo jet (this was when they still had them) gloomily smoking my "last" packet before rejoining militantly non-smoking parents in Canada. They lived in a mobile home perched on the rocky slopes beneath a mine several hundred miles north of civilisation. There wasn't much to do. Within days I was itching to smoke again. I felt a pang about stealing cigarettes from the kindly and inobservant custodian of the mine-shop, but if I'd bought a pack it would have been all round town by teatime. The next problem was how to escape from observation. I scrabbled up the steep slope and into the woods, where I lurked, puffing melancholically and gazing at the glacier. Occasionally I would leave off puffing and sample uncontaminated mountain air. Smoking just didn't seem as much fun as it was in London.

But what really pushed me into quitting, as well as the fact that the storekeeper was beginning to wonder why I kept hanging about, grinning vacuously and never buying anything, was the bilingual government leaflet: "YOU are in bear country!/ VOUS etes en pays d'ours!" A fascinating, if rather fatalistic, document, it pointed out that it was no good running away or climbing a tree since bears can run like racehorses and climb faster than you can. In fact any movement towards or away from the animal is considered bad form in ursine society, and would probably result in you having your head clawed off. The only hope was to play dead, whereupon the bear would drag you away and bury you (shallowly, it was hoped) for later consumption. Providing this procedure hadn't broken too many limbs, you would then be able to crawl away when the bear had cleared off. We knew the bears were never far away because they came down regularly in the night to forage in the town dustbins, leaving long scratches one night on our kitchen door.

Never mind the cancer risks: you can't have a relaxing smoke when you nearly have a coronary every time a pine-cone falls.