It's back! The best science-fiction TV series ever created is at last returning for its long awaited fourth series. And so, by a curious coincidence, is Doctor Who.

Yes, Battlestar Galactica really is that mighty. If your only knowledge of BSG is from its initial incarnation, a so-so space-opera starring Dirk Benedict in the late 1970s, that may be hard to take seriously.

But not only is the new show better than the original, it's also stronger drama than pretty much anything out there, give or take a Sopranos or a Wire. It's brilliantly written, perfectly played, and credits its audience with plenty of intelligence.

Meanwhile, Doctor Who has grown cocky. Confidence has turned to glibness, as the Doctor cheerily saves himself with a smart comment and a spizz of his sonic screwdriver. Can it ever again be the best science-fiction series around? Not on Battlestar Galactica's watch - here's why.

TOUGH OPPOSITION

BSG starts with the villains, the Cylons, knocking off billions of people - leaving the 40,000-odd survivors the sole remnants of humanity. Mankind's chief weapon? The rusty old spacebucket of the title. The Cylons' chief weapon? Having white-hot technology, looking human (handy for infiltration) and never dying. Cybermen? Daleks? Amateurs.

PEOPLE GET HURT

OK, Billie Piper got sucked into another dimension, and Kylie copped it. Other than that, though, not much really gets to our invincible Time Lord. In the ensemble BSG, there's always the danger that one of our heroes might die at any moment. The President (Mary McDonnell) has cancer; Admiral Adama (Edward James Olmos) gets shot at close range by one of his own crew, and several second bananas lose their lives as the show progresses.

IT'S NOT FOR KIDS

Which, OK, doesn't make this an entirely fair fight. But BSG depicts an adult moral universe that comes in lifelike shades of grey, where people must often choose between competing evils. Doctor Who, meanwhile, is a family show. You don't have to be a kid to enjoy it. But it helps.

SEX, SEX, SEX

There is sexual attraction in the Tardis, but thankfully no consummation. The rebooted BSG, however, was sexed up from the off, as super-sexy Cylon Number Six (Trisha Helfer) literally screwed secrets out of Gaius Balthar (James Callis). And while Number Six looks smashing in a cocktail dress, and the more rippled male cast members aren't averse to getting their shirts off, the sex isn't just titillation: it deepens the drama.

IT'S REALLY FILMED IN SPACE

It isn't? Well it certainly looks like it is. Respect to the special effects on the new Doctor Who, but BSG looks out of this world.

IT PLAYS A LONG GAME

You can't really watch BSG out of sequence, as each season has a shape. In last season's Doctor Who, on the other hand, the Master conquered the Earth in two episodes.

SCARCITY BRINGS VALUE

This fourth season will be its last, which means there's no time for the show to repeat itself. BSG episodes can be overcomplicated, but there are no actual duds. Doctor Who, meanwhile, has too many brisk one-offs in which the aliens barely have time to announce their grievances before they've been sassily outfoxed.

BREADTH OF REFERENCE

Doctor Who is the story of a superman hero. BSG is the story of a human society, and looks at the competing priorities of government and military, leader and worker, duty and desire. It also features sexy people in fetching outfits. In short, it's got the lot.

Battlestar Galactica Revisited, Tues, Sky One, 9pm (followed by The Phenomenon at 9.30pm & Razor, 10pm). The fourth series starts next week. Doctor Who, Sat, BBC One, 6.20pm

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