The news that Ridley Scott is to direct another movie in the Alien series that he kicked off in 1979 is bound to be interesting to true fans of the movie series in general, and the luminous original in particular. From the early 1980s I can remember articles, rumours and conversations speculating on this subject. Scott, Sigourney Weaver and so many others have put forward their own flights of fancy about a new Ridley Scott Alien movie, that it can scarcely be imagined that the new film live up to the weight of expectation.

As one commenter on our article about the news mentioned, it’s guaranteed at the very least that the movie is going to look fantastic; Scott’s visual stylings have influenced a generation of film-makers. Blade Runner alone remains a continuing source of inspiration for science-fiction movies and SF production design.

Some have argued that Scott is not the man he was as a creative force; the syndrome of ‘beginner’s luck’ can certainly carve out a name for a director who’s unable to maintain it (as a look at the output of William Friedkin after The Exorcist and The French Connection will attest).

What’s easy to forget about Ridley Scott is that he was nearly forty years old when he made Alien, and one of the biggest directorial names in TV advertising; he wasn’t a film school graduate looking to break into movies via ads and music videos, but a genuine established commercial entity committed to commercial interests. At heart, Scott is a craftsman occasionally beguiled by serendipity and inspiration, rather than a committed artist who has added technical skills to his repertoire. Scott is a journeyman extraordinaire.

What he isn’t is Paul Schrader; Scott will not be found shining a curious flashlight into the more obscure corners of the human mind and asking a major studio to fund an expedition there. The gloss is guaranteed, but the ‘magic’ is an optional extra. He likes to be genuinely excited about a movie he’s making - but if that doesn’t work out, it's going to get made anyway, and he won't be losing any sleep over it.

For Scott, 'hack' isn't a dirty word - he's a pragmatist dealing with available resources; he wants to make movies that are both commercial and have some sort of hook that interests him, in that order.

Perhaps he has been away from science-fiction too long - it seemed to engage him as no other genre did in a prolific career. But the now-legendary pain of making Blade Runner must have combined with its initial commercial failure to deal a body-blow to the director; it seems to have taken decades of the world admitting that Scott was right about Blade Runner to bring him back to screen sci-fi. The CGI revolution and increased scope for such projects in Hollywood wasn't enough in itself to bring him back to the future, until now.

Scott has always followed the money: The Duellists was a cinematic gem in the wake of Kubrick's Barry Lyndon; 1492: Conquest of Paradise an anniversary tie-in; Hannibal a clamoured-for sequel; and even G.I. Jane a second stab at the feminist theme of the considerably more interesting Thelma And Louise.

The luminosity of Scott was beginning to wane even by his fourth movie, Legend - a visual feast, but under-written, and a second box-office failure after Blade Runner to convince the director that the sci-fi and fantasy boom kicked off by Star Wars was played out. Scott started over in the safer and cheaper genre of film-noir, with the gorgeous but vacuous Someone to Watch Over Me in 1987.

He then embraced the ultra-violence of the late 1980s with the controversial but ultimately dull Black Rain, before capturing the public imagination again with Thelma And Louise. The 'heart' was back again…if only briefly.

Thereafter the nineties were not kind to Scott. Conquest of Paradise re-united the director with Alien collaborator Sigourney Weaver, and continued the director's confusingly varied love-affair with the period drama that had bought him his ticket to Hollywood in The Duellists (which affair continues as I write with principal photography of Robin Hood).

White Squall proved to be Dead Poets Society at sea, meeting critical and box-office indifference, whilst G.I. Jane seemed determined to reverse all the feminist goodwill that Scott had built up with Thelma And Louise, making a lot of people wonder if either he or writer David Twohy had suddenly become huge fans of Paul Verhoeven. But the controversy proved inadequate to pack out theatres, and the movie had to claw its budget back beyond the US market.

And then, at last, there was Gladiator. Those of us who wanted to see Scott return to SF and fantasy felt a pleasant, if distant shudder as the worlds of ancient Rome were astonishingly recreated, while the (admittedly largely fictitious) lives and loves of the imperial court proved irresistibly attractive material. Perhaps emboldened by the semi-unhappy ending of Titanic, Gladiator bowed out on a bittersweet note and Ridley Scott, finally, had truly touched us again.

Flushed once more with commercial and critical success, it seems that Scott went on an almost indiscriminate shopping spree for properties, and to no great effect: Silence Of The Lambs sequel Hannibal managed to disgust and fascinate, but not move; Black Hawk Down proved an uninspired tale of modern warfare in the middle-east; the anaemic theme and writing of Matchstick Men failed to provide Scott with another character-driven hit; and Kingdom Of Heaven managed to make even the Crusades excruciatingly dull (though it was interesting to see Scott finally work with Jon Finch, who had played Kane for one day on the set of Alien before being diagnosed with diabetes and replaced by John Hurt).

Always eager to capitalise on former success, Scott re-united with Russell Crowe for the pointless and ineffectual A Good Year, the lively but empty American Gangster and the not-even-lively Body Of Lies. Whether the Scott/Crowe 'period'-magic will return in Robin Hood, we'll have to wait and see.

God knows, the man seems determined to pop his clogs on set, considering the huge raft of projects he is set to helm in the next six or seven years. An occupational psychologist might suggest that Ridley Scott movies could benefit from being less frequent but more deeply-considered, but the man's career doesn't bear this out: Scott's return from a four year absence in the nineties brought us only the unambitious White Squall. Scott thrives on adrenaline and movement, but creatively he's a one-armed bandit that keeps the coins trickling out but only pays a jackpot out once a decade.

And we, who love Alien, would prefer it if Robin Hood proved the pot-boiler and Alien 0 that moment of rare and serendipitous inspiration in the Scott production cycle. It's the fact that Ridley Scott can still surprise us at all that will keep even those who suffered Kingdom Of Heaven coming to his movies.

Could it be that Paramount have shown Fox the way by really getting behind J.J. Abrams' Star Trek, and breaking the franchise out of the nerd ghetto? And could it be that Alien 0 proves the most committed and well-funded of any of the Alien movies? In a way I dread this - the higher its ambitions, the more that demographics will dominate the set-up and production of the prequel. In my heart of hearts I want to see Scott struggling with limited resources to create something truly chilling and effective, not surrounded by a gaggle of high-level investors who want to make sure that all the boxes are ticked.

Ultimately, in either scenario, it's Ridley Scott, and what passion he can prove for the project, that will decide if it's just another curiosity in the Alien saga. Will Alien 0 be one for the money or one for the show, this time? Will he care, this time? The man is a visual genius, but when he goes beyond that and finds the content behind the gloss, Scott is capable of the best that cinema can offer us.

• Official: Ridley Scott to direct new 'Alien' movie
• The plot-obstacles to an Alien prequel
• Ridley Scott in talks with Fox for Alien 5
• Ridley Scott's return to sci-fi
• Ridley Scott for Forever War