There’s no point in trying to phrase this nicely: ‘Demons’ is bloody awful and the first true disaster of the Saturday night adventure shows that have followed in the wake of the BBC’s hugely successful ‘Doctor Who’ revival.

Whatever you may think of ‘Robin Hood’ or ‘Primeval’ or ‘Who’ itself, these are successful shows which have found an audience. It’s hard to see who would be satisfied with ‘Demons’ though.

The premise is this: a teenage student inherits a great destiny to fight demonic creatures, helped along by a middle-aged man from the other side of the Atlantic called Rupert who bases himself in a library. Oh, and the hero’s mother is oblivious to all of this.

Yes, it’s early ‘Buffy’, just relocated to London and slowed... down... to... a... crrrrrawwwl. You would have thought that, when aiming to grab a slice of the ‘Doctor Who’ audience, the makers of ‘Demons’ might have ripped-off the precision with which ‘Who’ slams home it’s fantasy concepts and characters to a mixed-age, early evening audience (an efficiency repeated in the first episode of ‘Merlin’, presumably thanks to Russell T Davies’ advice as a consultant) .

But no, ‘Demons’ takes an age to unfold and explain its not-exactly-brain-surgery premise (‘it’s the secret magic world in Harry Potter, but with more monsters and fighting’ would cover it). It’s not like the producers are trying to slip an adaptation of ‘Naked Lunch’ on to prime time ITV. The kids can handle it, especially when the plots are so painfully, for-God’s-sake-have-a-biscuit thin.

It’s like they got the Incredible Hulk in as a storyliner: ‘Bad monster man do bad thing. Good people hit with sword, or shoot with gun. Bad thing die. Hurrah! It all over now. Hulk want line of coke before puny Banner wake up and demand smoothie.’

Where was I? Thin premise, thin plots, all overdrawn, and in the case of the second episode, spectacularly tasteless in its crude, ripped-from-the-headlines topicality. On a more detailed scripting level, the dialogue never really falls over too badly, but instead placeholders along without ever giving the faintest suggestion of an interesting world, or that the characters might have personalities beyond their stereotypical plot roles.

Sadly, while some actors might bring flatly written roles to vibrant life, the ones in ‘Demons’ don’t. Leaving aside the widely reported... oddness... of Philip Glenister’s US accent in the role of Rupert Gavin, he doesn’t do much other than growl generic Americanisms and berate his young charge. Both he and Christian Cooke (playing slayerboy) have a stiff lipped, slightly miffed demeanour, as if someone just ripped off their moustaches with sticky tape and they’re trying not to cry.

There are a couple of girls, one of whom is supposed to be blind, which you can tell because she’s always staring slightly away from the camera. In fact, the strongest reaction any of the characters provoked in me was Saskia Wickham as slayerboy’s mum, mainly because the fact that Wickham is playing a mother makes me feel so bloody old.

What else? There are some werewolf hoodies who look like they’ve escaped from an urban reimagining of the Beatrix Potter ballet. The lighting uses the strong pinks and greens of a provincial ghost train, and in more naturalistic settings varies from shot-to-shot as if the actors have been filmed on different sets, even when they’re standing right next to each other. The end product has the feel of a classic ITV botch job – they have the money, on paper they have the talent, but the actual production feels rushed, incoherent and inept. There’s no fine-tuning, no finesse, just a shoddy scramble through a slippery gravel pit of TV fantasy clichés.

It’s hard to believe that ‘Demons’ comes from Shine, the same production company that made BBC1’s far better ‘Merlin’, and even harder not to blame the quality gap on the differing culture’s of the two broadcasters. (Then again, Shine did churn out the abysmal ‘Hex’ almost simultaneously with the excellent ‘Sugar Rush’, so maybe they’re just wildly inconsistent.)

Since Christmas the TV schedules have gone very quiet, certainly as far as drama is concerned, leaving a window of opportunity for even an average programme to make a mark with audiences. The ratings reveal the extent to which ‘Demons’ has failed to capitalise on the lack of competition, with a sufficiently severe drop between the first and second episodes that, if the downward trend continues, ITV might feel obliged to move it to a less important time slot before this season is out.

Certainly, unless some miracle occurs, it’s very hard to imagine this being re-commissioned. If it does, it really will mean the forces of darkness have overrun us.

Mark Clapham's first comic strip, 'Nomads', is published in the 'Zombies' anthology from Accent UK .