The night before Joan Jett and the Blackhearts' first UK gig in 20 years, I watched the 1980 teensploitation flick Times Square. The character of Nicky Marotta could have been based on Joan Jett: do(p)e-eyed, delinquent, sexually ambiguous and living for nothing but dumb rock 'n' roll.

At the gig the following night, I catch a glimpse of Jett posing for a photoshoot, backstage at the 100 Club. She looks like the pictures I used to cut out of Kerrang! and stick on my homework diary, to offend my headmaster. She looks like a proper rock star of the kind I idolised as a kid, but one I'd forgotten about.

On stage, the Blackhearts backdrop looks faded and crinkled enough to be the original from back in their heyday. It looks like it's soaked up some sweat in its time. The audience are mostly as you'd expect - old punks, old rockers, old music journalists... Everyone hoping to hear the five or six truly great songs that forged the mould for Riot Grrrl, Girl Grunge and beyond (into the carefully packaged teen rebellion of Avril Lavigne and clones).

They start, just as Joan's solo career did with 1981's 'Bad Reputation' which, as starts go, is pretty much unbeatable. The band, still featuring her original co-writer and producer Kenny Laguna sound exactly as you'd want them to: raw and nasty but impeccably tight. Her voice is perfect; it hasn't aged a day (though admittedly it always sounded like the singing voice of a hardened whisky drinker).

Joan flashes the crowd that unmistakeable smile of hers, the one that says: "I'm about to do bad things and get away with it." You can see why they'd make a movie about her; Joan Jett is Hollywood's idea of the perfect punk. Though whether Kristen Stewart can deliver that on screen is doubtful. The Runaways' 'Cherry Bomb' is also dispatched early. It's still an extraordinary blast of a song, undiminished by the numerous attempts to copy the template ever since. But even the less familiar, more recent material sounds just fine. There are no go-to-the-bar moments. Like The Ramones before her, these are songs designed to get in and get out as quickly as possible, doing their job with calculated efficiency and little deviation from the original formula.

'I Hate Myself For Loving You', 'Do You Wanna Touch Me', 'School Days', 'Crimson and Clover', 'I Love Rock 'n' Roll'... she plays them all and they all sound just like they do in your memory. But this doesn't feel like nostalgia, just hot, sweaty, sexy and timeless. There seems no reason not to have Joan Jett and the Blackhearts back in our musical lives. They should be playing all the festivals, this year. They should be worshipped by indie kids half their age, at ATP. Why did we ever care about Courtney Love when we had Joan Jett? She's been missing from this country for too long. Maybe the film will change all that. Unless it's shit.