I was interested to read, in our review, how the producers of Life On Mars (US) handled the thorny issue of smoking in the first episode of the time-travelling cop drama. In the Brit version, brute-with-a-badge Gene Hunt (Philip Glenister) was finally faced with a fag-free future (in the sequel Ashes To Ashes). This was because of new restrictions on smoking in the workplace, including the BBC studios where 12,000 herbal cigarettes had previously been consumed for UK Life On Mars.

That certainly makes Ashes To Ashes the right title for a follow-up. It's the way of things - even arch-puffer David Bowie, who supplied the initial theme song to both the UK and stateside versions from his back catalogue, quit the habit five years ago.

There's no point in re-igniting the very thorny polemics that tend to flare up between the abolitionists and the libertines regarding the subject of the influence of smoking in films and TV. Rather, let's presume that the impetus to rid the world of cigarettes by bans, restrictions, taxes, education and every other means available to the anti-smoking lobby will prevail, even against the might of the tobacco industry and its lobbyists and advocates.

What, then, are we going to do about the century of screen smoking that sits enmeshed in the very best - as well as the worst - output of cinema over the last 100 years, and television over the last 60 or so? And how can we convincingly omit a practice that was almost universal at a period in time that new historical drama - such as Life On Mars US - might be attempting to depict?

Since 'retro' became so magnetic and profitable - from the sale of old US TV shows in large and affordable DVD box-sets, to actually setting a show like Life On Mars in one of the smokiest and grittiest periods of New York's 20th century history - this is about as thorny a problem for the anti-smoking contingent in Hollywood as it could possibly be.

In the Life On Mars pilot show, as our review noted, people are seen with lit cigarettes, but hold them as if they were incense sticks. Clinton-like, there's no obvious inhaling going on. You can almost see the elaborate storyboarding and political wrangling behind the depiction of smoking in Life On Mars US - the compromises, the arbitrators, the wrangling, and the legally-required presence of the New York Fire Department as soon as one of the shabby tecs lights up a herbal fake in an enclosed set.

By the most conservative estimates, 40% of male adults were smokers in the US in 1973. You can probably add a few percentage points for stress-driven jobs like police work, and loads of points for the criminal fraternity, so any cop drama set in that period is going to have to look smokey or it's going to have to look 'wrong'.

There are three interested parties here:

- The creative forces (writers, directors, etc) who use the depiction of smoking not only to provide a quick and dirty shorthand for general historical context, but also - as in George Clooney's Goodnight And Good Luck (2006) and David Fincher's Zodiac (2007) - to recreate an event, period or person with reasonable historical accuracy.

- The tobacco lobby, who have been as keen to promote their product in movies as any other industry, and more successful than many.

- The anti-smoking lobby, whose objection to the continuing 'promotion' of smoking in US movies and TV is compounded by the 'tobacco paradox': its belief that the tobacco industry was in any case creating all the smoke that shows like Life On Mars US must now recreate for reasons of historical accuracy (see link in previous paragraph); thus making the cycle of 'addiction by media osmosis' - as the anti-smoking lobby believes - circular and hard to break.

The solutions for historical drama are not clear, but obviously you can't continue to have historical characters nursing cigarettes that they never smoke. Nor can you claim that all your characters fall within the non-smoking bracket in whatever period of history you're trying to depict - even the most rudimentary understanding of demographics won't support it. Unless you set your drama in a fireworks factory, a nursery or Skylab, it's real hard to keep a year like 1973 tobacco-free.

Back in the present, screen smoking is evolving rather than just going away: exiled smokers now gather together to convene amongst themselves outside in all weathers, which is proving a romantic/gritty new scenario for films like My Blueberry Nights.

With the re-glamorisation of fractured or damaged characters (which significantly preceded The Dark Knight, whatever Hollywood may think), the anti-smoking contingent's previous insistence on 'demonising' smoking acts is getting too risky a bet: if the hero's a villain, and so is the villain, then who the hell gets to light up? Neither? Both?

Negotiations between the anti-smokers and the creatives have also led to some very clunky scripting trade-offs, where cigarettes are frequently removed from the packet but never lit; this happens to Martin Sheen immediately before his murder (smoker's karma) in The Departed, and to Kate Bosworth, whose heroic suitor won't let her light up in Superman Returns. But most often it's the Sheen/Departed treatment for the nicotine-addicted: out comes the smoke, and over the side of the building goes the smoker, almost magically punished by the MPAA, like the knights who give the wrong answer in the 'bridge' scene in Monty Python And The Holy Grail.

It's fake. The audience - smokers and non-smokers, advocates and resisters alike - can smell the propaganda like a lit Gauloise on a bus. It isn't subliminal enough. It breaks story, movie and mood, and undermines the realism that the director is usually working so hard to achieve. It's the kind of proselytisation found in far more soporific quantities in USA children's TV; but here in a significantly more expensive product that's notionally aimed at adults.

In the meantime the tobacco industry rubs its hands at the cultural loophole that lets historical drama fill the silver screen with a miasma of tobacco; for it, Hollywood's future is definitely in the past.

Smoking has been such a part of the film-maker's core language since the days of Méliès that trying to excise it can prove to be like trying to type out a book with several common consonants prised off the keyboard. Lighting up on-screen became short-hand for so many expressions of character and mood over such a long period of Hollywood and US TV history, that it seems as hard to give up as the habit itself. On the other hand you could also call it a cliché; one might hope - even wish - that writers and actors stretch their imagination further to develop an equivalent cinematic idiom with more versatility and depth.

The tobacco industry - if you believe the anti-tobacco industry - has done its work well over the past 60-70 years, and not even a decade of double-overtime at ILM and Weta Digital combined could remove the rafts of smoke from Hollywood's heritage. In certain cases, removing scenes of smoking would leave you only with the opening and closing credits; if that.

What's left? Will new DVD releases of old classics find classic children's films snuggling up with skin-flicks and torture-porn on the highest rack in Blockbuster? Will every scene of smoking now have to be accompanied by a lengthy subtitle warning from the surgeon general?

The move to drive smoking onto the streets has been a sweeping storm of legislation in Europe, America and (increasingly) Asia over the last decade, but there seems no way that Hollywood and US TV can excise the evil weed - particularly not from its enormously lucrative back catalogue - at the same dizzying speed without destroying the appeal of the product. If you want to look on legacy screen smoking as a cancer, then it's quite possibly inoperable.

Not even the most successful bodice-ripper or adaptation of Dickens has ever succeeded in bringing back the demand for snuff as a consumer item, and the aim of the current anti-smoking movement in Hollywood seems to be that we one day regard screen-smoking with the same bewilderment as that extinct habit. At that point, we may be permitted again to enjoy the best of classic cinema without caveats, warnings or absurdly inappropriate maturity ratings.

But while 20-25% of the Western population still smokes, the tobacco paradox will continue to contribute to the problem in the form of legacy content; in what's already 'in the can', on our screens, our re-runs and in our DVD players. The struggle to get that 20% of smokers in the population down to 0% will still prove to be the (continuing) work of decades rather than years if we're to do it without another Volstead act. In the current depressed mood, bringing with it a wistful atavism for times and styles past, it's not the easiest moment for Hollywood to detox.

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