Can you imagine Humphrey Bogart chewing gum instead of smoking in The African Queen? Or Clint Eastwood rolling up his poncho to slap on a nicotine patch? Or how about Gandalf in Lord of the Rings putting away his pipe and taking up sudoku?

Smoking has always been a popular crutch for the Hollywood screenwriter. It can signify sexiness or sophistication, or be a convenient way for one character to get to know another. Robert Redford, playing the experienced CIA man in Spy Game, tells trainee Brad Pitt that he must carry cigarettes and a lighter around to strike up conversations and intimacies. And Campbell Scott's womaniser in the sex comedy Roger Dodger is appalled to hear that his young nephew wants to seduce girls but doesn't smoke: "You'd better start!" In art as in life, smoking is seen as a far-too-easy way to speed things along.

So why is there more smoking in the movies now? Anti-smoking campaigners say it can only be because Hollywood is still getting under-the-counter promotional money from big tobacco. In 1989, an informal "self-regulatory" ban was introduced, after product placement verged on the scandalous: in Superman II, Lois Lane - a non-smoker in the comics - chain-smoked Marlboro, and Philip Morris reportedly got its brands on to the screen in Who Framed Roger Rabbit? and The Muppet Movie. Activists suspect that cigarette companies are finding discreet ways of making payments, and have no qualms about targeting their wares at under-age consumers. The companies deny it.

But there is a sense that even without sponsorship cash, Hollywood likes to use fags. Like big tobacco, the studios are in the business of selling pure pleasure, and they are not averse to letting the crowds in non-smoking cinemas inhale a little instant gratification by proxy. Like cigarette companies, Hollywood increasingly covets foreign markets where smoking equals attractive American-ness. In India, they are making smoking in the movies illegal. We are very far from that in either Hollywood or the UK. Perhaps ethical directors of the future will include more cancer ward scenes.