Interpol/The Gossip, Reading Festival

Interpol, that perfect iPod band of nattily dressed New Yorkers, take their brooding sound to the great outdoors

The difficulty with Interpol has always been in taking them quite as seriously as they take themselves. From the very beginning, despite the self-evident quality, nay magnificence of the music the Manhattan quartet made, and no matter how pleasing their sonic textures, there was something quaintly, endearingly comical about their blatant desire to be Joy Division, and laugh-out-loud preposterous about some of their lyrics (most infamously "subway is a porno", and "you're stabbing... yourself... in the neck!"), particularly when delivered in a portentous baritone such as Paul Banks'.

In their case, however, presence has made the heart grow fonder. Repeated exposure to Interpol softens you up, and suddenly something just clicks. In my case, it was walking into a crowded bar just as "Slow Hands" – that gloriously elegiac combination of lingering emotions and accelerated guitars – came on the jukebox, and it felt as though Interpol were reading my mind and writing the score.

This, you see, is how Interpol are best enjoyed. The angst that these alumni of the private New York University evoke is the angst of the privileged – think Bret Easton Ellis's Less Than Zero or Whit Stillman's Metropolitan, or, to get really old school, F Scott Fitzgerald's The Great Gatsby or Evelyn Waugh's Brideshead Revisited – but that has its time and its place, even for an inveterate class warrior. When you're feeling, to quote Brett Anderson, "cinematic and tragic in black and white", Interpol are there for you, the soundtrack to your personal biopic. They're the perfect iPod band.

What they aren't, however, is the perfect festival band. This is, in many ways, to their credit. They're a blast of cleanliness in front of a crowd of muddy urchins. Guitarist Daniel Kessler and bassist Carlos Dengler are in suits and shades, à la The Matrix. In his red shirt and black tie, drummer Sam Fogarino looks like a member of Autobahn, the fictional krautrock band in The Big Lebowski. Paul Banks, too, is dapper in a dark shirt, his cute birthmark next to his nose making him look forever 12 years old. It's no surprise, as they step out and start up "Pioneer to the Falls" (the opening track from their quite wonderful third album Our Love to Admire), that there are girly screams: women love few things more than handsome young men dressed like gents.

A band as intimate and claustrophobic as Interpol should not, in theory, work in the wide open spaces. But something, subtly, has changed. If there hasn't been a progression in their sound per se, there's been a shift in its scale, itself an emulation of their career path. Our Love to Admire – their first record on a major label – sees them move from a claustrophobic whisper in the ear to a widescreen epic.

And so, even though there's something inherently wrong about watching Interpol in daylight, they nevertheless manage, with a set which alternates between crowdpleasers such as "Obstacle 1" and "Evil" and new material such as "The Heinrich Maneuver" [sic] to place you elsewhere.

As the sun sets and the set closes with "PDA", I realise what's actually happened. I've come a long way. Interpol have stayed exactly where they are.

I never planned to write a review of The Gossip, but I cannot let a show like theirs pass without comment. This is my 21st Reading Festival, and I've witnessed some extraordinary performances in that time, of which my absolute favourite was Porno for Pyros in 1992, which featured Perry Farrell breaking off to berate the hecklesome crowd. Extract: "Listen to me. I'm 37 years old, and I'm cooler than any of you." It's an accolade bigger than Beth Ditto herself when I tell you that The Gossip are right up alongside that.

Ditto is, of course, a character with charisma to rival Farrell's, and with twice that of the rest of the day's white indie boys combined (from whom I shall pick hopeless Libertines copyists Little Man Tate as today's Worst Band in the World, perhaps unfairly, but in the knowledge that the crown will be stolen later by Razorlight).

Beth bounds breathless from the airport in a borrowed purple dress which is five sizes too small and soon turns into a top when she wriggles a few times and it rides up over her ample hips (and eventually comes off altogether), a matching disc-shaped party hat and beautiful Siouxsie eye make-up. She apologises for being late, and tears through a scorching set which punctuates The Gossip's own raw, minimal garage-disco-blues-riot-grrl thing with snatches of "Rehab" ("So much respect for Amy Winehouse"), a self-mockingly gluttonous adaptation of Haddaway's "What Is Love" ("When is lunch? Baby I'm hungry, I'm hungry, for more..."), and a bit of bitching which brings a mixture of boos and cheers: "As Madonna said, music makes the people come together. Although I'm not convinced that she said it. Someone else wrote it, and told her to sing it."

Stamping barefoot so that her cellulite ripples rhythmically and screaming with both passion and precision, she proves that her voice doesn't only possess that nebulous quality "soul" but also sheer technique. (There's never a bum note.) In a different era, she'd have been a disco diva. The fat lady sings.

They close with a Stanley knife-sharp version of "Standing in the Way of Control" which is so thrilling that you forget that you've heard it too many times, and even forget how much you want to punch that kid on the Skins trailer clean out of that bloody "field of dreams we're dancing in". And that is really saying something.

Further browsing Bret Easton Ellis, a literary companion for Interpol: