Last Night's TV: Gossip Girl ITV2<br />Ashes to Ashes BBC1

At first sight, Gossip Girl comes across as a junior version of Sex and the City, with its cast of unnaturally preened Manhattan types blathering on about clothes and shoes and who's been seen with whom. It wasn't until about 10 minutes in that it hit me that it's trying to do something entirely different. It actually wants to be The Catcher in the Rye for the MySpace generation. Like J D Salinger's great novel of adolescent disillusion, it is set among the children of the fashionable rich of the Upper East Side. These children have every expense lavished on them – they all go to swish prep schools – and they all have a veneer of sophistication, polished up through liberal applications of cocktails and soft drugs. But in essential ways, their lives are empty; they are loveless, confused, desperate. Meanwhile, the adults around them (mothers who share their teenage daughters' dress size and think that "put some product in her hair" counts as advice and comfort; dads who make their sons get back together with recently chucked girlfriends because they could blow a big business deal with the girl's parents) are all a bunch of goddamned phonies.

At the centre of all this confusion are Serena van der Woodsen and her former best friend, Blair Waldorf, known to each other, and to the omniscient narrator, as B and S, as in brandy and soda or... well, you work it out for yourself. As the programme opened, S's return to Manhattan was setting the mobile phones and social-networking pages a-buzzing. Some time earlier, S, having been the ultimate party girl, had undergone some mysterious crisis and gone into self-imposed exile at an upstate boarding school. Details such as this, by the way, are conveyed by that omniscient narrator, who is the Gossip Girl of the title. GG is the nom de keyboard of the person who runs a fervently followed website devoted to documenting the party-going and rivalries of New York's jeunesse dorée. GG knows everybody, sees everything, and yet manages to remain both completely anonymous and, with her know-all intonation, terminally irritating.

The plotting is both convoluted and boringly familiar: B loves Nate, but Nate has a thing for S, who is in turn attracted to new boy Danny, whose sister, Jen, adores S, and whose dad turns out to be an old flame of S's mother. Whenever this gets dull, local sleazebag Chuck – clearly a kind of J R Ewing in training – sexually assaults somebody (both S and Jen inside 20 screen minutes). I'm hoping this rather nasty plot device is underplayed in future episodes, not that I'm likely to be watching myself.

What distinguishes this most obviously from home-grown froth such as Hollyoaks or Skins is the money visibly sloshing around, which says something about the difference between the US and us. I don't think any British teen drama aimed at a mass audience could concentrate so unselfconsciously and unironically on the doings of the upper crust.

Actually, a little more self-consciousness and irony wouldn't do any harm. As it is, the series often verges on the unintentionally funny: occasional sequences of frantic text-messaging and the website device seem awkward, coming across as a faintly desperate attempt by the producers to show that they're "down with" what's "happening" with the "kids". There are other problems: at one point, Chuck, meeting S in a bar, cracked a joke about serving minors, which would have worked better if Blake Lively, who plays her, didn't look thirtyish. But this is a perpetual problem for teen dramas, as you'll know if, like me, you used to turn on Dawson's Creek just to snigger at the steady encroachment of male-pattern baldness on James van der Beek's supposedly 18-year-old hairline.

Meanwhile, Ashes to Ashes came to a sort of end, with Alex Drake (Keeley Hawes) thrust back in time to 1981, rushing to prevent her parents' murder, and failing. One problem here was that I couldn't work out what difference this was supposed to make to anything (given that we know this was all going on in her head, what effect could success have had?), and therefore couldn't get terribly worked up. The denouement did contain a twist: the bomb that killed her parents turned out to have been planted by Alex's father, bitter because her mother had found someone else. This was unexpected (to me, anyway), but also unconvincing, partly, I guess, for the simple reason that it was a resolution, and in real life those are rare.

But I don't suppose anybody watches Ashes to Ashes for the plot. You watch it for DI Gene Hunt and his old-school views on women, ethnic minorities and gays ("Our pillow-biting friends," as he amusingly referred to them here). By now, though, that particular joke has worn a little thin. You could feel the writers struggling to find new epithets, new ways of being outrageous, while also succumbing to an urge to sentimentalise him. If they'd had the nerve to make Hunt a good old-fashioned pig, instead of a softie at heart, I'd have liked the series better.