Murphy is a peculiar mix, and quite prickly. She spends much of the interview eyeballing me, which I'm convinced is partly to do with her lifelong passion for fashion (she is perhaps not overly impressed with my Top Shop ensemble), but is nonetheless disconcerting. As for what she's wearing, "the top is YSL (Yves Saint Laurent) and I bought it for signing my record contract. This is a vintage solid gold and silver belt, and my boots are Margiela, the avant-garde Belgian designer."
On the one hand Murphy is very open. Although she is about to bring out her second solo album, Overpowered - a brilliantly pure disco and dance record and her most accessible work to date - she is still happy to talk about Moloko's painful demise four years ago, which also spelt the break-up of her eight-year relationship with musical partner Mark Brydon. "It wasn't like an intense week or month, it was more like an intense two years," she says.
She is also happy to discuss the recent spat with Scotland's own electronic popster Calvin Harris, who was rather publicly miffed when Murphy failed to use tracks he had done with Cathy Dennis for Overpowered. "He got upset, didn't he?" she agrees. "I don't hold it against him because I was like that myself when I first started in the business. I was very reactive and a journalist could get me going very easily. I'm still quite easy to get going, but I'm not as bad as I was." She saw Harris recently, she says, and he apologised profusely, saying that now he's heard her album, he understands. The tracks have since been taken up by Sophie Ellis Bextor.
Yet when asked whether she is searching for a wider, more mainstream audience with Overpowered, her first album signed to a major label (EMI), she is more cagey and tends to say things like, "that's your job to say, not mine".
"I'm definitely still trying to carve out a place for myself," she later concedes. "It's still tricky to rationalise what I am and I don't feel I can sit back and put my feet up. But I've got no interest in being in some trendy ghetto. There is a perception that I'm very left-field, but the bottom line is when you put me in front of people I can connect with them. I don't want there to be a misunderstanding about that."
There's no doubt that Overpowered marks a new phase in Murphy's career and could be the breakthrough she seems to both crave and resist. Moloko may have been most famous for the huge pop anthems 'Sing It Back' - which featured on 110 music compilations - and 'Time Is Now', but the band was always much weirder than that. Moloko was an outfit that, even after 'Sing It Back' stormed the dancefloors of Ibiza, continued to put out songs with titles such as 'If You Have A Cross To Bare You May As Well Use A Crutch'. You'd be more likely to see Murphy milking a cow in a suit of armour halfway up a Swiss Alp, as on the cover of Moloko's second album, or pigging out in a greasy spoon while wearing a clownish, pom-pom suit (the album artwork for Overpowered) than pouting in a mini dress.
Murphy is closest in music and style to, say, Alison Goldfrapp, and it's no surprise that she is a huge fan of iconic performance artists such as Grace Jones and Cindy Sherman. Overpowered is influenced by the stripped-back disco of the late Seventies and the synths, hooks and squelchy sounds of early house music. It's co-produced by Andy Cato (Groove Armada), various other uber-cool collaborators were involved and, though there are cheesy moments - the new single 'Let Me Know' being an unfortunate case in point - it's a thrilling trip to the dancefloor. There are murmurs about Murphy making an assault on Kylie's fanbase. "I'd rather be compared to David Bowie," she says. "But it's not my place to tell you what to write."
Murphy's first solo effort, Ruby Blue, was released just two years after Moloko's last. A collaboration with the brilliant and rather bizarre Matthew Herbert, Ruby Blue was a fascinating sonic experiment that included the sounds of notebooks being hit across microphones and a sample of a "seaplane leaving for Tofino". It was acclaimed, but it didn't sell by the bucketload. So, now that she's signed to a major label, is she concerned that EMI will want to tone her down? "They can try," she says, with a husky smoker's laugh. Her accent by the way is a curious hybrid of Ireland (she is from Wicklow), northern England (she's spent much of her life in Manchester and Sheffield) and cockney (she now lives in London with her boyfriend, who is a visual artist).
"It's not easy sometimes," she says. "This is not like other jobs because what I'm doing is selling myself. I'm on top of everything I do, every image I make, every piece of music. I try to put as much of who I am into my work. I'm quite a naked performer, so at the end of the day if you don't like it, you don't like me. I'm an intense person... my boyfriend says I'm a nightmare to go out with."
Everything she has ever done has been recorded, she explains. When Moloko started she had no experience of singing or performing. The story goes that as a cocky teenager in Sheffield, Murphy bounced up to Mark Bryden at a party with the chat-up line, "do you like my tight sweater?" Evidently, he did, and those immortal words ended up becoming the name of their first album. Prior to that, she had no intention of becoming a singer, which for those who know her gorgeous, silken voice, is hard to believe.
"I hated singing," she says. "I learnt 'Don't Cry For Me Argentina' when I was eight and sang it for my family. Their mouths were all wide open." She starts laughing and feigns an exaggerated Irish accent. "Aw, she sounds just like Elaine Paige!" Her family moved to Manchester when she was 12, and then when she was 15 they moved back to Ireland. Murphy, though, stayed, a teen on her own. Bullied at school, she started hanging out with "a bunch of weird boys who wore black and listened to Jesus and Mary Chain".
"I started dressing in Sixties clothes, wandering around Manchester wearing a red pantaloon suit and red handbag. I buried my singing voice. I mean, I was listening to Sonic Youth: I didn't want anyone to know I sounded like Elaine Paige."
So, she has never been a conformist, and even though Overpowered could well be her crossover album, don't be expecting a watered down version of Roisin Murphy anytime soon. "At the age of nine I had long blonde hair and I took my pocket money and went and got a flat-top," she says. "When I came home my dad cried his eyes out. I had to do confirmation looking like a marine."
• Let Me Know is out tomorrow, the album Overpowered is out October 15 on EMI. Roisin Murphy plays Glasgow ABC on December 1 www.roisinmurphy.com