On stage, the Daughter singer is poised and mysterious.

“When I was a solo artist, I found it very, very difficult,” says the 23-year-old, with the first of many nervous giggles.

“There is nothing worse than playing in a pub or a club, or what have you, where absolutely nobody is interested. You are singing, they are talking loudly. It can destroy your confidence. It’s easier if there are three of you. You know you have somebody at your side. It makes a difference. I’m sure a solo career works for some people. It didn’t suit me at all. As a musician, I’m self-taught and felt I was restricted by my abilities.”

Daughter have been on taste-maker radars since 2011. A series of dark, haunting EPs, released on Mumford and Sons’ Communion Records, has seen them anointed as the up-and-coming talent in ‘nu folk’, though their sound is neither new nor especially folkie. If they have antecedents, it is ’80s indie goths, the Cocteau Twins, and the Icelandic post-rock outfit, Sigur Ros. The fuss, Tonra says, can be overwhelming.

“I remember, before Christmas, we were asked to appear on the David Letterman show, in America, and I worried if it wasn’t too soon,” she says. “I’ll be honest, my first thought was ‘we haven’t got a record out — so what’s he going to hold up to the camera as he introduces us?’ As it happened, he had one of our EPs. We really enjoyed it and received a good response. Still, you do think, perhaps, it is a cart-before-the-horse situation.”

As Tonra says, her career as a singer-songwriter was going nowhere when, at a music course in London, she met Igor Haefeli, with whom she started Daughter. They are romantically involved. What about that old musician’s stricture, ‘don’t make money with your honey?’ She laughs. “We see our music and our lives as very separate,” she says. “Igor doesn’t question my lyrics. He regards what we do as an art form. He certainly doesn’t try to rewrite my words. I never tell anyone what my songs are about, not even him. I feel they are direct enough, anyway. They aren’t especially obscure.”

That said, sometimes people get the wrong impression, she says. “I have songs that can be about a dark subject. And then someone will say to me, ‘oh, that’s a love song, isn’t it?’ And it will be about as far from a love song as you can go. Sometimes, performing older material, even I’m surprised by what I’ve written. Your relationship with your music develops with time.”

The press release accompanying If You Leave claims Tonra is channelling demons through her music. She is slightly thrown by this.

Giggly and down-to-earth, she does not seem like someone with the weight of the world pressing down on her. As musicians go, she seems strikingly normal.

“I think ‘demons’ might be slightly overstating matters. I hadn’t read that, actually. On the other hand, it’s true that everybody has a dark side. There is stuff I keep to myself, stuff which, if I didn’t write about it, maybe it would consume me. So, I don’t know, it could be ‘demons’ is true, in some way. Of course, I appreciate the irony of my having all these subjects I never talk about — and then going on stage and singing about them. It is a bit of a contradiction.”

Tonra has written songs since she was a teenager. Shy and bookish, at school she was bullied. Music was her way of coping.

“Writing has been how I deal emotionally with life. Some 13-year-olds have to go through a lot of really horrible stuff. I think my upbringing was normal. I did feel lonely. There was a sense of being left out. I changed schools aged 12 and that affected me in a big way. I have carried on writing about things I feel difficult talking about in adulthood,” she says.

Tonra’s grandfather is from Dublin and she grew up immersed in traditional music. Perhaps that explains the air of Celtic melancholy that infuses If You Leave. In the UK, Daughter are often likened to Enya, The Cranberries and Sinéad O’Connor. Tonra doesn’t quite know what to make of this. She didn’t set out to sound like Enya.

“I suppose, I listened to a lot of Irish music when I was very little,” she says. “I would not say it is a conscious influence. As a child, it is possible it seeped into me and shaped me. I think that is entirely plausible.”

Tonra was initially daunted by all the attention flowing Daughter’s way. With the album about to be released, she has, to her surprise, achieved calm. It’s too late to change direction now. What will be will be.

“I was nervous, because it’s our first record and we’ve worked on it all year. However, with only two weeks to go I feel relaxed. The album isn’t perfect, which is difficult for me to admit, as I am a perfectionist. There are elements I would still like to tinker with.

“But you reach a point where you have to leave it go. Our EPs aren’t perfect — which gives them character I think. You can’t control absolutely everything.”

* If You Leave is released Mar 15