"Accessible" isn't a word one would ever be likely to use in describing Anaal Nathrakh. "Frightening" is probably better. Named for a line from Merlin's Charm of Making spell in the film Excalibur, the Birmingham duo's seamless fusion of black metal, grindcore, industrial and whatever else they feel like playing is consistently repulsive to the uninitiated and endlessly rewarding to the patient.

The band has been eviscerating listeners on wax since a pair of well-received 1999 black metal demos and reinventing themselves to varying degrees on nearly every record since without ever compromising an ounce of integrity or identity. The project spent its first six years of existence without playing live, but in 2005, V.I.T.R.I.O.L. (vocalist Dave Hunt) and Irrumator (multi-instrumentalist Mick Kenney) enlisted guest musicians for the first-ever Anaal Nathrakh gig – a one-off Christmas show at the Underworld.

One Sunday night in May, they returned to the Camden club as a part of a still-rare European tour. Their set focused largely on 2001's underground classic The Codex Necro ('The Supreme Necrotic Audnance', 'Submission Is for the Weak', 'Pandemonic Hyperblast') and the still-forthcoming Passion ('Volenti Non Fit Iniuria', 'Drug-Fucking Abomination', 'Paragon Pariah'). We sat down with the guys before the show to talk about when music can be scary, their memories of the Underworld and some surprising sources of aural inspiration.

When you first started playing live, you only really did one-off gigs, but now you're in the midst of a proper European tour. Why the change of heart?

Mick Kenney: Found a drummer.

Dave Hunt: It's that easy, really.

MK: Basically, when we first started, it was quite – I won't say original, but no one was really playing that fast and that crazy and we just didn't think it was physically possible, but now that we've found a guy who can do it, we've started meddling around even faster.

DH: There's a sort of misconception about whether or not we had some kind of vow not to play live in the first place. I've done a few interviews where they've tried to say 'No, no, you were totally against it.” No, we just didn't. That's a totally different thing than having some kind of commitment not to.

Tonight's gig is a return to the Underworld, where you played live for the first time.

DH: There were two gigs we did here that were particularly memorable. The first Anaal Nathrakh one. The capacity of the place is probably 500-550, and there were 750 people in there the first time we played it. It was ridiculous, when in fairness it was the Terrorizer Christmas party and it wasn't necessarily just us. But then we did another one with Mistress, the other band we used to be in. We supported Napalm Death, and I'd like to think we had some small part in it and it was the combination of bands in the lineup, but there was a queue all the way around the building and it was savage that night. And also, I remember coming here and seeing Clutch and I was only 18 or so. It was quite some time ago and I remember thinking 'I'd love to play here. Imagine if I had a band who could headline here.'

In addition to being an extremely heavy band, some of your music is deeply unsettling to some. Is being frightening an intention?

MK: Not really, no.

Do you feel that the music can be frightening when you finish it?

MK: Honestly, we don't really think about what we're making. For example, if I write a song, that's how it sounds, and when Dave does his vocals, that's how they sound. DH: But we to tend a bit to the horrible stuff.

MK: Yeah, we do. But it's not like, 'Oh, let's make this sound horrible.' It's more 'Let's make this sound how we like it,' and it just happens that it comes out that way.

DH: I do like unsettling music. I had an ex-girlfriend and I used to talk to her...well, I used to talk to her. [Laughs] But I remember talking to her about scariness, not because I knew you were going to ask this question, but she said 'I don't think music can be scary.' I thought, 'Fair enough.' Got a big stereo at home and it was late at night, roundabout midnight. So I turned all the lights off, drew the curtains, put The Omen soundtrack on and played it so loudly it could kill small animals, and at the end of track one I pressed stop and looked at her, and she went, 'Alright, yeah. Okay.' And I really like that quality in music that I listen to, so I suppose it might be that we like that, so it comes out when we do it.

Let's talk for a second about the guest vocal spot on Passion on 'Tod Heutet Uebel' from Rainer Landfermann. I found that vocal performance to be particularly frightening. How did you guys hook up with him, and did you give him some direction as to what to do on the track?

MK: Minimally so.

DH: We listened to the album that he did with Bethlehem, which I think is amazing.

Great record.

DH: And then we like to have guests just to make things interesting, just to have something unexpected. I got a hold of the name of the band he's currently playing in called Pavor, a death metal band from Germany, and I found their website and I sent an email saying 'I don't know if it's Rainer that gets these, but this is a message for Rainer, and we'd really like to do this if you're up for it,' and he replied and said 'Maybe.' And we had to convince him. So I had to write the lyrics and a long-hand explanation of the idea behind the song and we sent him the music so he could listen to it, and then he just went 'Yes! Brilliant! Fine! Amazing!” And he replied back that night saying 'I've just spent four hours arranging vocal parts!” And he just went barmy.

MK: He'd be ringing me up all the time and telling me about what he'd done and making sure it was okay, and he can't speak English very well so there'd be these long silences.

DH: And he'd insist on these phone calls. We'd say, 'Alright, is this Rainer?' 'Okay, yeah,' expecting him to have some point that he wanted to make or something. MK: And he'd just be like 'Hi.' [long silence]

DH: But I actually read a review that I thought got it quite nicely, that characterized quite nicely what he's done with that. He said 'Most of the time, it sounds like the perpetrator. This is the music of the perpetrator. Whereas this becomes the music of the victim.'

I like that.

DH: I like that way of putting it.

That's exactly how I would describe that. Sticking with Passion for a second – great album, by the way; I really enjoyed it – but it feels a lot to me like a fusion of all your eras and sounds. I can hear elements of The Codex Necro as much as I can hear elements of In The Constellation of the Black Widow. Was that conscious on your part?

MK: Not really. It's like, we don't purposefully try to write an album in that particular way, but it's going to have bits of every album in it because that's what it sounds like when we write it. So we don't really try to be different, but every time we do a new album something different happens. I don't really know what's different about the new album, but it kind of was a bit different.

How much do you think about whether some riff or lyric is 'Anaal Nathrakh enough.' Is there some standard that when you write a riff you know that it fits the band or it doesn't? Or have you written a riff and said 'I can't use this for this band'?

MK: No, not really, because I don't really write music like that. I kind of just have a thing in my head and I'll go 'Ah, right, I've got a cool riff' and I'll just play it.

DH: You get the sensation in your head first.

MK: Right.

DH: It already enters into a mindset where anything he writes on a guitar will be Anaal Nathrakh.

MK: Yeah. I've never really agonized and gone 'Ah, I can't write a riff!' I'll wait until it's already there then I play it and go 'Done. Finished.' It's quite easy, really.

DH: I know with lyrical stuff as well whether it's appropriate. If it's something that makes me sit there and go 'Fucking hell,' then that's it.

If it disturbs you at some level then it's acceptable for the band.

DH: Yeah.

On the subject of lyrics, what literary influences have been creeping in lately with the new album

DH: Right. Well, the last one had a fair amount to do with Jens Bjørneboe's book Moment of Freedom, whence the album title was really a play on. So that book was the first of a trilogy called History of Bestiality, so there's a little bit from the second book of the trilogy which is Powderhouse, and that's where 'Who Thinks of the Executioner?', the song from the new album, comes from, with maybe a few other bits and pieces that it was influenced by. With this one it was more academic writing, actually, because I've been doing a university course and I've been exposed to it more. There's an avant-garde philosophical journal called Collapse, and there's a paper in that about conceptual horror, so there was some stuff involving that in 'Drug-Fucking Abomination'. It isn't drawn from that, but it's sort of seen through the prism of it. Some stuff by a 19th century German philosopher called Max Scheler who only ever wrote one book and then disappeared into obscurity, he was the most thorough-going nihilist I've ever come across. You can have exceptions with people who just ruin themselves and their lives and they're sort of nihilists by proxy, but he was an academic thoroughly read up and was strongly convinced that this was the case. Wrote a book which is fucked-up and didn't bother anymore. A few papers on multiple personality disorder and stuff like that. So, a few different things. Quite a lot.

Obviously for all of your albums either academic or literary influences have found their way into the lyrics. Do you hope that people will go home and seek out these books and read them themselves? Is that part of your intention when you write these lyrics?

DH: It's not an intention to make them do so, and it's not a requirement for them to do so. I did an interview with an American site the other week and he said 'Well, after I read that the last album had to do with this Jens Bjøernboe book I went out and bought it and read it.' That felt a bit like a victory, in a way. So it's cool if people do that, but it's not intended as an entrance exam or anything. Music doesn't have to be all up there [motioning to head], it's in here [motioning to heart]. So if that's the basis on which someone gives a crock about Nathrakh, then fine. If they are willing to try and are interested to find out, then I like the idea of them doing so.

Do you find it easy to segregate yourself as an academic and yourself as an extreme metal singer?

DH: I don't recognize the distinction.

MK: Same thing.

DH: Same thing, and there's lots of other things. You're a person. There's not some kind of a specific exercise that's being done when one thinks. You're just you, and when you think something, you're still you. So I find it impossible to separate the two.

Then you don't mind whether somebody takes from your music the academic aspects or just the sheer intensity of the sound.

MK: Well, you can't really, can you? People will take from it what they want. We just do it because that's what we do, so if they like it, that's cool. They can take what they want from it.

Let's talk about influences for a second. As you've developed over the last decade as a band, when you hear a new band that excites you, do they become an influence, or do you still have a similar set of influences that you had in 1999?

MK: It's quite hard to get inspired by new bands these days. I feel that from a music point of view a lot of stuff that I was influenced by was better than stuff that's happening today. So it's kind of hard to get excited by a lot of music. I think what we like about music is a lot about feelings and atmospheres and things like that, and older bands were more creative and original in trying to make new sounds. Bands these days are more about doing this, this, this and this and getting on this label and putting it out. I know it was only ten years ago, but 'bands back then.'

Yes, way back in 2000...

MK: Well, yeah. But when we were younger, we were into music that was already older too.

DH: But by the same token, a lot of those people are still knocking around, aren't they? A lot hearken back to the 60s.

MK: Yeah, I think a lot of the bands that we were into were bands that were trying to make new music that they didn't know about what they were trying to do. So it wasn't a genre that was already made, it was developing. We just took bits and pieces we liked from all of them.

And in so doing, you sort of did the same thing.

MK: Well, yeah, kind of.

DH: As a sort of microcosmic example, when you think about black metal nowadays, there's a certain uniform, a certain style of dress, most people wear some kind of makeup on their face, and blah blah blah blah. But if you were there at the time for the early stuff – Mayhem, Burzum, that sort of stuff – they all sounded totally different to each other, and they all had different ideas. They thought 'What can I do that sums up this evil feeling I've got in my head,' and one said 'I'll do this' and another said 'I'll do this.' There was no identikit thing going on at all.

MK: And it's not just the black metal stuff. It's the death metal stuff as well. Those bands did the same thing as well.

DH: Well, that was just an example. The idea of someone pushing forward.

MK: And we just articulate the bits of each band that was the most horrific and meld them into a new sound. There was no big purpose to do that, it's just getting inspired by different things.

Do you believe metal's become too homogeneous?

MK: I have no idea.

You don't keep up anymore?

MK: Nope.

DH: Well, I definitely think it is, insofar as I'm exposed to it or aware of it. I don't always try to seek things out, but every now and again something comes up. In the interview I did a few minutes ago, he brought up Fleshgod Apocalypse and I heard their first album twelve months ago or so, and it was brilliant. It was the last thing I've heard that was really new. Usually, that thing's not metal, and it hasn't been for some time. There seems to be an awful lot of Lamb of God and an awful lot of...

MK: It's just standard heavy metal music. It's never really bothered us that much. It's just ordinary music. We like stuff that sounds weird. We like, I don't know...power drills.

DH: One of the most exciting conversations I can remember us having on sound was on the Underground in London. On the train, someone left the window open and you could hear all the clattering as it was going through the tunnels, and everyone else is just sitting there reading the newspaper, and there's me and him in the corner of the carriage going 'Ah, listen to that, mate! Ah, can you hear that? That's brilliant!' But that's just what we're like. [laughs]