The new NME girl who dared take on the might of Simon Cowell

So meeting 27-year-old Krissi Murison, the first woman to edit the weekly title in its 57-year history, is refreshing. With her bob, alabaster skin and on-trend pencil skirt, she bears more than a passing resemblance to the actress Maggie Gyllenhaal.

Krissi Murison: "There is a huge percentage of people out there who don't like what The X Factor does. It gives everyone something to kick against"

This week Murison has pulled off a cover interview with "The Antichrist" himself. Simon Cowell — the man who filled the charts with karaoke acts — is a hugely controversial figure for the NME, which is spearheading a campaign to make Rage Against the Machine's Killing In The Name a Christmas No 1 this ­Sunday, in an attempt to stop X Factor winner Joe McElderry claiming the top spot with The Climb.

Let battle commence: Joe McElderry may have won The X Factor but he now faces an NME-backed campaign to get Rage Against the Machine in the Christmas No 1 slot with Killing In The Name

In fact, she rather liked Cowell. "I went in imagining him to be defensive about some of the questions, maybe a bit upset, even riled, but he really wasn't. He doesn't pretend that he is a passionate music fan. Or even really likes it that much. He knows what he's making is light entertainment and he's very successful at that."

Simon Cowell: "He doesn't pretend that he is a passionate music fan — or even really likes it that much," says Murisone

The NME cover has the tongue-in- cheek headline "The Grinch Speaks". But Murison takes the Cowell effect ­seriously. "The X Factor started off as such a freak show, something you could laugh at, but it's turned into such a big, glossy event. It is dressed up now as this is the biggest music show on TV'. It's no longer a talent show."

She'd love to see Cowell showcase interesting, undervalued artists. "He says he makes the show to change people's lives. But actually it's a corporate ­platform — where all the biggest-selling artists, from Robbie Williams to Whitney Houston, go back to perform."

After boosting Leonard Cohen's bank balance with the royalty cheque from Hallelujah, last year's Christmas No 1, Cowell is in benevolent mood. In the interview the funniest moment is when he says grandly: "I'm thinking of doing something for David Bowie next year."

"Bowie could never have existed if he'd come up through X Factor," Murison tells me. "He's the opposite of that. He'd have been voted off in the first round for being weird. It scares me how we're eroding the mystique of the pop star."

Murison was on the NME for five years and spent six months in New York this year as music director on style magazine Nylon before being poached back to the NME as editor. "We were having an absolute ball and had just made a great group of friends. I was, like, No, no, no', but my husband Ollie was saying, Yes, yes, yes. You've worked so hard for that job for so long'."

Murison's appointment was universally praised. Rock critic Lucy O'Brien ­compared it to the Anglican church letting in women priests. "Young female writers now have a role model and a sense that they too have a right to report on the rock world that inspires them."

But then Murison's tenure makes sense, coinciding with an extraordinarily rich year for female singer-songwriters — Florence and the Machine, La Roux, Little Boots, as well as acclaimed second albums from Lily Allen and Lady Gaga.

Murison is wary of dwelling on the issue of gender. "I got this job for many reasons, none of which had anything to do with what sex I am. My first introduction to the NME office was as an intern seven years ago and now I'm coming back as editor — every single door that could ever have been opened to me has been."

Instead of banging on about women and music, Murison thinks "the real story right now is, where are all the boys?". Good point: these days the indie guitar bands seem to be roaming the wilderness.

She thinks it's because great bands such as The Libertines, The Strokes and Arctic Monkeys were so successful that the record companies charged in to sign the next big thing. "It became a bit of a conveyor belt. All the rough edges were sanded down and smoothed out."

Murison grew up in Hampshire, ­suffered from acne as a teenager and studied English at Bristol, where she wrote for the university newspaper. NME took her on at 21. Part of her success can be put down to her omnivorous musical taste: Murison is no snob. She loves Girls Aloud and thinks Lady Gaga "might be a genius". "Dance music is really exciting again with things like dubstep. And Dizzee Rascal is bringing grime to the mainstream."

She really likes the way today's teens are "non-tribal". "It's not rock kids versus indie kids versus pop kids," she explains. "And I think artists are responding to that by mixing things up."

NME has had a tough time recently, with circulation down 24.3 per cent last year (though previous editor Conor McNicholas, now editing Top Gear magazine, extended the brand into online radio and TV and live music tours).

The criticism by some fans is that McNicholas turned the NME into an "indie Heat" (its cultural peak was in the Seventies and early Eighties when Chrissie Hynde and Julie Burchill worked there).

So will Murison change direction? She's been talking to older critics such as Paul Morley who are more interested in the socio-political context of bands. But she is not afraid if more adult readers fall away. "If NME was being read and created and accepted 100 per cent by people who are 40-plus, I would say we were doing something really wrong."

After New York she could look at NME with "fresh eyes". "I was getting it airmailed over every week. It's still my favourite magazine in the world."

Just as well, because her job is 24/7. When she was first dating Ollie, she was NME new bands editor, he was a music scout, so they'd do five gigs a night together. The consequence is she never goes out at weekends. "I don't think anybody in the music industry does. When it comes to Friday night, all you want is a takeaway curry and a DVD."

But first, there is important work to be done in her battle with Cowell. "The bookies are having to slash the odds for the Christmas No 1," says Murison, "which shows there is a huge percentage of people out there who don't like what The X Factor does. It gives everyone something to kick against. Over the past few years there has been some great music in the mainstream charts and maybe we've got complacent. But now if you look at the top 20, it's really shocking."

But often the best music comes at the darkest hour. "The two most influential bands in London at the moment are The Horrors and The XX. Last night I saw a band called Factory Floor at Corsica Studios, they're very punishing and dark in their Kraut-rock rhythms.

"Things are bubbling under. In a couple of years this X Factor dominance will be taken down — and taken down in a really spectacular fashion," she tells me, a gleam in her eye. Simon Cowell, you have been warned.