"People think I'm boring," she says. "I'm far from it. People say, 'Oh it's so boring' about my music, and maybe IT'S boring but I'M not boring. 'Boring' is a word I wouldn't identify with. I'm a lot of things, but boring isn't one of them."

Thus speaks Sarah Joyce, the artist better known as Rumer, when I ask her what she thinks the biggest misconception about her might be. She answers with zero hesitation, suggesting that 'boring' is an accusation she's heard time and time again. The evidence, though, leans toward the contrary. Sure, she isn't outwardly weird, in a showy, freaky, pop star diva sort of way. But she's quietly, understatedly eccentric. You notice it in the smallest hints, here and there. Like the way she takes her dog Alfie absolutely everywhere, including the red carpet of the Q Awards at the Grosvenor House hotel, and the Grand Hotel in Brighton, where we conduct this chat. Alfie, you see, isn't a tiny designer handbag-chihuahua à la Paris Hilton or Kim Kardashian, but a full-sized lovable scrappy mutt from the rescue centre. Or like the card I received from her a couple of Christmases ago, containing frantic crossings-out and the scribbled question: "Are you the one with the wife? I can't remember." What with one thing or another, I've slowly pieced together the impression that Rumer is indeed a lot of things, but boring isn't one of them. But does the B-word hurt?

"I don't know if it's the medication," she says (of which, more later), "but I just don't care any more. Once you've seen it - 'You're fat and ugly and you can't sing' - once you've read that 20 times, it's like, 'Oh this is just so childish. This is really silly. And just embarrassing.' But yeah, things hurt, when people say things that aren't true, to be mis-characterised. Because every single person is interesting and complicated, with a dynamic and a whole history, and multiple dimensions. And to be abbreviated down to something two-dimensional is unfortunate, and can be very upsetting."

The two-dimensional version, of course, runs something like this. Child of an English expat family, born in 1979 in Islamabad, where her father is working on the construction of a hydroelectric dam. Only finds out, years later, that she's half-Pakistani because her mother had an affair with the cook. Spends her teens in Carlisle and Devon, and her twenties between London, living in a caravan in the New Forest with her mother, until her mother dies of cancer, and a commune in the south of England. While waitressing in London, she makes various attempts to get a singing career off the ground, most notably with La Honda, who never quite make it. A chance encounter with composer Steve Brown, best known as bandleader Glen Ponder from Knowing Me Knowing You With Alan Partridge, leads to a fruitful musical relationship and her debut solo album, Seasons Of My Soul. Showcasing a voice which, as almost every review mentions, bears an uncanny resemblance to that of Karen Carpenter, Seasons Of My Soul is an album on which, as Pete Paphides noted, "every song sounds like a standard". It sells in platinum disc-earning quantities, as does the follow-up Boys Don't Cry, a collection of covers of songs by male-only artists. What few people realise is that, around this time, she's suffering from a major bout of depression (hence the aforementioned medication). Her third album, Into Colour, recorded at RAK Studios with Burt Bacharach's arranger Rob Shirakbari (after a split with former collaborator Brown), is largely inspired by the experience of dealing with that depression, and coming through it to the other side.

In the run-up to its release, she's been remarkably candid in speaking out about mental health issues.

"When I first started talking about it, it was more taboo. It's less taboo now to talk about the lack of provision. There's no provision at all, unless they see you running down the street naked... then they put you in high security. There's no preventative care. So that's a time bomb. And all these young people brought up in these traumatic environments, that's a time bomb too. For me personally, which is all I can really talk about, thank god it's in the rear-view mirror. I've had one major depressive episode in two years. I feel like the amount of time between episodes is getting longer, so I'm pleased with that progress. But I'm under supervision, I'm on medication (though not very much), and I have a dog, and I've created a better environment to feel safe in. It's one thing having mental health vulnerabilities, but it's another being in situations that trigger them off."

Like being in the spotlight and chained to a record industry treadmill, where your time is no longer your own?

"Yeah. Losing control of your life is a trigger. For some people it's eating disorders or stuff like that, that's a method of control. But it's not just people who are famous. I've been in high security, visiting someone, and it's mainly just people off the street, who have gone too far and been thrown in there. It's the guy who loses his wife and kids because she says, 'I'm leaving you, I've met someone else', so he sets fire to the house.

"There's a song on the album called 'You Just Don't Know People' that relates to that. That song's very important because it's about anger management. It's about not losing your shit, basically. To climb inside someone's mind and talk them down off a ledge. It's a compassionate record. It's very much like, 'I've been there'. There isn't very much that's coded. My lyrics are 'say what you see'. I do like coded things too, I like listening to a Kate Bush album and going into Kate Bush's world and exploring that. But do I relate to it? Not really."

In terms of style, Rumer very much does what she does, and those platinum discs speak for themselves. Making a radical break would be a risky strategy. Into Colour is, accordingly, a gradual development upon its predecessors.

"I think people might associate Rumer with smooth, easy listening 70s-style music," she admits, "and I don't know if it's a major departure from that. It's definitely more orchestrated and sophisticated musically, it's warm, it's more upbeat, and it's positive. It's less introspective, it's less, 'Oh, woe is me, I'm a girl in her late 20s searching for her soul', and more active, and making more social commentary."

Social commentary isn't something with which she's been associated in the past.

"The main one is 'Play Your Guitar', which is about encouraging musicians to not give up their craft. Because what incentive is there? You can spend your whole life investing in equipment and investing in your skill, only to be treated like someone who doesn't get paid to do a gig and is expected to do everything for free. Anything else you make, people know that they have to pay for. People don't give any value to music, even though it's something everybody wants. But somehow it's been devalued. Obviously, some people just aren't talented enough. Not everybody's meant to do it. But the people who are really meant to do it, are still in bed. We've got to really help people. And that's useful for mental health as well, to help people channel their feelings into creativity. It's not necessarily about struggling musicians trying to get signed. It's about a sensitive person trying to express themselves through a creative thing. A lot of people who are too scared to pick up an instrument and even try, but the point is to be play-ful. Creativity is important, both for people who are skilled and people who've never done it before. That should be encouraged."

Easier said than done, of course, in a climate where labels won't invest in artists, so only those with money already behind them get the breaks. The posh pop takeover.

"People probably think I'm posh. But I'm from one of those families where maybe there was money once, probably 20 years before I was born, and you're living in the shadow of that, where you've got older brothers who had a private education but the divorce happened and everything kind of ran out, and it's gone, it's all checked out by the time you're five years old. But yeah, being in a band was a way of escaping the shit you're in. Not any more. It's very hard. I was very lucky to find Steve [Brown], because he invested in me. And whatever's gone down between us, I'll always respect that. Fair play to him for that."

Rather than pulling the ladder up after her, as others might, Rumer is actually putting her money where her mouth is.

"I've started a record label called Night Owl, and it's an adult contemporary label that's developing people who maybe aren't the first to put their hand up and get noticed. I'm running it with Ann Marie Shields, who is the sister of Kevin Shields from My Bloody Valentine. We've got a band called The Golden Retrievers, who are like Bread, and a project called The Church Of Malcolm, which is the guy behind La Honda, the band I did my first record with. He's a great songwriter, and a big personality and man about town, but he went through this difficult experience with leukaemia and nearly died. And he came back from intensive care with all these songs. So I said, 'Fuck it, life's too short, let's make this album that you wanna make.' And Duffy's gonna be in it, I'm gonna be in it, and other random characters. So this label, Night Owl, is meant to facilitate art, and to contribute towards culture. A collective of people who want to help people."

I'm struck, I tell Sarah, by the way she talks about Rumer as a third-person entity, as though it's a persona which allows her to shield her true self from prying eyes.

"I think it's helpful, even just ringing up a bank or something like that, to have a different name. And it's healthy to have a separation. But I've always had a duality: half Pakistan, half England, that combination. I've always felt there are two sides to me, two aspects. It's healthy to have a stage persona."

I wonder whether the widespread idea that Rumer is 'just' a singer means that she is underestimated as an artist.

"It's funny, because the first album was mainly me. I gave Steve 20% on three songs, just for a piano arrangement, but I pretty much wrote it all. And produced it by myself. Maybe people need more evidence of my writing ability."

Could it be that people were so blown away by the singing on the first album that...

"The voice stole the songs' thunder? Well, this time we've had the Karen Carpenter comparison, so hopefully let's focus on what she's saying. I think people want something meaningful, and they're interested in what you've got to say, and what the stories are. Because what will never die is that human beings love a bedtime story. Even if it's tittle-tattle, office gossip, we cannot resist a story. Even if it's trashy magazines, it'll never die. And that's why music will never die. No-one really cares who's singing it deep down. The song is king."

Which seems a good point to talk about the albums which are king in Rumer's heart.

Into Colour is out now via Atlantic Records, with the album's next single, 'Reach Out', following on January 12 2015. Click on her image below to begin scrolling through Rumer's choices