"You can never trust journalists," he says, shooting me the same look that Nice Guy Eddie gives Mr Orange in Reservoir Dogs when he realises that Orange is an undercover cop. It isn't pleasant. Outwardly, Andy remains as amiable as he has been all evening, and the contrast between his soothing tones and his steely James Cagney glare only adds to my unease. So: it's going to end here, at the hands of the dyed-blonde disco diva responsible for such lyrics as "I try to discover a little something to make me sweeter" and "Why is life so precious and so cruel?" and "Yahoo-waa! Higher! Higher! Higher!" (Yes, what was all that about anyway?)
"You always get the feeling you're being stitched up," he continues, not shifting his eyes from me. "You can do an interview and have a good time and they'll seem like the nicest person in the world. Then you read their article and you just think, 'Oh, you prat!'."
Does that happen much?, I ask cautiously.
"Quite a bit," comes the terse reply. He may not realise it, but Andy Bell is quite an expert at intimidation. Get a journalist alone with you. Make small-talk. Offer him a beer. Then tell him you think he's come here to report on what a failure you are, and watch him crack under the pressure. It's the sort of technique that tax inspectors spend years perfecting. Naturally, I deny such accusations. After all, Erasure have a special place in my heart. They were the first band I ever saw in concert: 1988, Hammersmith Odeon, I was 15, and if you'd told me then that within a year I'd be pretending that my first gig was actually Prince at Wembley Arena, I would have replied that there was more chance of me ending up in Andy Bell's dressing room being accused of plotting a stitch-up.
Andy's paranoia is not altogether surprising. Erasure have long been a convenient punch-bag for anyone who loathes disposable synth-pop. And, for that matter, anyone who doesn't. They've been called derivative and vacuous. They've been ridiculed as Pet Shop Boys Lite (mostly by the Pet Shop Boys themselves). In short, they haven't had it easy.
But the past few years have seen what little credibility they ever possessed vanish along with a considerable portion of their sales. The greatest hits album Pop!, released five years ago, was the last time that Erasure can truly be said to have been at any sort of creative or commercial peak. The collection charted the band's career from their formation in 1985 to their first number one single in 1992 - over half of the singles featured on it had swept effortlessly into the top 10.
It didn't matter if you despised "Sometimes" or "Victim of Love" or the winsome "Chorus" which, with its "fishes in the sea" line, scored the biggest victory for illiteracy in the top three since Chas and Dave's "Ain't No Pleasing You". None of this was relevant. Once heard, these songs were - often maddeningly - never to be forgotten. And for a time, the contradictions that arose from the combination of the flamboyant, caramel-voiced Andy and the shy, bookish techno-wizard Vince (fresh out of commandeering Depeche Mode and Yazoo) had a smack of tension tangible in Erasure's shows, if not their songs. But nothing they've done since the No 1 success of the "Abba-esque" covers EP - not the albums I Say, I Say, I Say, Erasure or the latest release Cowboy - has had the same impact as those earlier infectious electronic nursery-rhymes.
In retrospect, was it wise to release "Abba-esque"?
"Yeh," shrugs Andy. "It was all right. But people forgot we wrote our own songs. People thought we were just this complete drag band. And we did become unsure of ourselves for a while. We did a small tour last year just to see if the audience was still there. We had no idea whether anyone would turn up. We're hanging on by the skin of our teeth, really."
Is that how you feel?
"Sometimes. It's awful when you start thinking not enough people are buying the records, or you're not being recognised enough. You start getting moody if you don't get the star treatment. The vibe we're getting in this country is, 'Oh, you're over because you don't have a top 10 single.' That gets depressing."
Will Cowboy win you any converts?
"I dunno. We wouldn't mind some younger fans."
But do Erasure fit in 1997?
Andy: "I don't think we've ever been hip."
Vince: "My mother says all our stuff sounds the same."
Andy: "So do a lot of people."
Vince: "Well I think they do. Not that it worries me particularly. They're all different songs, aren't they?"
Andy: "The Beatles sounded the same for years, before..."
Vince: "Every band has its peak, you know? But you can't expect it to carry on forever. That's the nature of pop music."
What happens after you've hit that peak?
Vince: "You're supposed to die gracefully I suppose. We're just refusing to."
I think Vince's words are intended to signal strength and defiance, which would be admirable if you got the sense that Erasure were trying to thwart some indomitable foe - disco Davids battling their own personal Goliath. But as a band, Erasure have rarely sounded driven or motivated. There are no passionate emotions coursing through their work, despite the fact that many of the songs concern love - blossoming or unrequited, but always celebrated. And yet their choice of cover versions - "River Deep, Mountain High", "Gimme, Gimme, Gimme (A Man After Midnight)" - suggests that, deep down, they are striving to make music that will leave an indelible imprint on the soul. I wonder what makes them tick. So I ask Andy where the lyrics come from.
"They're all made up," he says bluntly. "It's just me wanting to be a torch singer, but not being tortured enough."
Have you ever written a politically motivated lyric?
"Someone told me that in America people were marching around during Gay Pride chanting "Chains of Love". That's nice. But I don't think I've ever come up with anything overtly political."
You once said that your song "Witch in the Ditch" was about Margaret Thatcher.
"Did I? Oh, I'll say anything."
But aren't there things you feel strongly about?
"Well, I'm really out of touch now. I don't go out. I never read the press. Something awful could be going on and I wouldn't know about it."
You never go out?
"It's true," says Vince, nodding. "He never goes out. He stays in his bedroom. In his bed."
"Cos I'm a junkie!" Andy roars. "I'm a fucked-up junkie!"
Cue nervous laughter - an unspoken acknowledgement that we've all heard the same rumours.
We leave the dressing room and make for a tiny balcony from where we watch the support act, Heaven 17. Andy visibly loosens up a little, venturing miniature dance moves in his seat, while Vince maintains his usual demeanour of quiet concentration. It's from the same seat that I will watch Erasure's own show an hour later. They provide their customary kitsch cabaret routine, and the more durable numbers are put through some rigorous tests - such as when Vince plays guitar while dressed as a cactus during the plaintive "Ship of Fools", a costume decision that could potentially capsize this fragile song, but which appears only to feed the audience's enthusiasm. As breezy as the gig undoubtedly is, there's something tiresome about the whole routine, which is epitomised by the camp Wild West theme - this is iconography that Erasure already explored a full 12 years ago in the video for their very first single, "Who Needs Love (Like That)".
Not that the fans are troubled by such matters. At a gathering of fan- club members after the concert, I meet a number of rabid devotees who unload anecdotes about catching 4am ferries or hitching lifts with serial killers just to see Erasure play some aircraft hangar in Outer Mongolia. Sadly, the much-mentioned Norman the Nutter has not been admitted. Norman presented himself to Janet, the head of Erasure's fan club, earlier on, bearing gifts that he insisted upon delivering in person. He had made a hat for Andy and a necklace for Vince. On this occasion, Norman returned home unfulfilled. But I talk to Jonathan, who runs the fan club alongside Janet. He inadvertently grasps the essence of Erasure.
"They're one of the few bands around who have no image," he explains. "They don't care what they look like. They've never had credibility. Yes, their music sounds the same, but that's what they do. No one else does that. They do it best. So they'll keep on doing it."
Another beer, another cigarette. Erasure are talking America. That's where they're headed. America wants their souls - Madonna's own record label Maverick is currently playing footsie with them.
"It's quite surprising," muses Vince with characteristic nonchalance, "because things have gone adrift in the UK and Europe, and now, suddenly, in America there's this enthusiasm for us. It seems there's an electronic revival going on over there."
Vince: "That's the thing. We're not sure".
Andy: "Apparently it's us and The Prodigy. But we're up for America now. Whatever they want, we'll do it. Whatever it takes."
As the night presses on, the conversation dissolves into idle gossip. Who's been signed, who's been dropped? And did you hear the latest about the Spice Girls...
"Oi!", Vince shouts, halting Andy mid-revelation. "He's recording!" He gestures to my Dictaphone, then looks slightly embarrassed. "Am I suspicious or what?"
"That reminds me," Andy says. "You were right about that girl from The Express." He turns to me. "She came out to Dallas to meet us, then went back and wrote this piece about how it's all over for us. I thought she was OK, but Vince was a bit wary. Bad vibes."
Vince fixes his impenetrable shark-eyes on me.
"You never can tell," he says coldly.
'Cowboy' is out on Mute records