Anvil: A mockumentary or real documentary?

Minutes into the film, about a forgotten Canadian heavy metal band called Anvil, we're presented with grainy archival footage of a ludicrous-looking group of young guys in bondage gear, enthusiastically playing guitars with dildos. Contemporary testimonials from giants of the metal world may be intercut with their performance, but there's something a bit too This is Spinal Tap about it.

In what appears to be a groaning reference to that film's director, the drummer is called Robb Reiner and as the film progresses, catching up with Anvil a little over 20 years later, with Robb and his best friend, guitarist and singer Steve "Lips" Kudlow still trying to make it, the Tap references continue to come thick and fast. Far from being an elaborately executed hoax, though, everything you see on screen is real, though the confusion is deliberate.

"The whole point was to encourage people not to believe that it was real," says the film's British director, Sacha Gervasi, nibbling on some lunchtime sushi as he sits alongside Lips, Robb and Anvil's long-term bass player Glenn "G5" Gyorffy in a restaurant ahead of the film's Scottish premiere at the Glasgow Film Festival. "It was structured in such a way so that you wouldn't be sure, so when the story turned, it really turned in a way you weren't expecting. People expect it just to be funny because it's about heavy rock, but by the end of the film, it's completely not that. We're really using …Spinal Tap as a Trojan horse to get to the audience."

Feature documentaries often tread a fine line between entertainment and exploitation. Chris Smith's hilarious 1999 Sundance Audience Award-winning American Movie (which bears a thematic similarity to Anvil…) sparked debate about the extent to which films of this nature condescend to their subjects, with indie filmmaker Todd Solondz so disturbed by the uproarious audience reaction to that film that he explored the phenomenon in his own movie Storytelling.

The deliberate blurring of documentary and mockumentary in Anvil… means there's plenty of potential for laughter at things that are actually quite sad and painful. Has the band experienced moments of discomfort like that?

"Not really," says Robb. "We laugh at a lot of it. But the people, I don't know, they seem to be crying. So we're seeing other stuff going on."

"I said to the guys right at the beginning, 'People are going to laugh at you in the first 20 minutes of film and that's all part of the journey, you just have to accept you're really funny,'" says Gervasi. "But it's not like they don't get it (the …Spinal Tap parallel]. These guys are totally self-aware.

"But I understand that sense of discomfort too, and I think that seems to be why the film is working," he adds. "On the one hand you're kind of looking at these characters from the outside, but you're also identifying with them. It's not just funny, it's not just emotional – it's all blended up together, which is what life is."

Actually, watch Anvil… for a second time and the film it overwhelmingly brings to mind is The Wrestler, with the band's refusal to give up on their first love – long past the age at which others would have packed it in – bearing striking parallels with Mickey Rourke's poignant character arc in that film.

"Absolutely," agrees Gervasi, Lips mumbling his approval beside him. "Nobody's really said that yet, but there's definitely some comparison."

What's remarkable – and different – about Lips and Robb, however, is the absence of regret or bitterness in their story. That was one of the things that fascinated Gervasi about them – and, indeed, it was what brought Anvil back into his life. Having befriended Lips and Robb when he was 16 after seeing them play in London in 1982, Gervasi actually used to go on tour as their mascot/roadie – though they eventually lost touch as he went off to film school and carved out a successful screenwriting career (he co-wrote Steven Spielberg's The Terminal).

"What was interesting to me was that all the bands that they influenced – Metallica, Anthrax, Slayer – went on to sell millions of records and Anvil never really made it,' explains Gervasi. "I never knew what happened to them."

Randomly looking them up online, he was shocked to discover they'd kept going and so he wrote to their website. Within an hour he got an e-mail back from Lips and, shortly after, he flew out to Los Angeles. "Within 20 minutes it was as if no time had passed," says Gervasi, who wasn't yet thinking about a film. "What was surprising was just meeting Lips again and seeing the way he was just so enthusiastic and actually believed that Anvil were still going to have their day if they just kept going.

"That was so inspiring that I started to get into the idea that it actually was going to happen for Anvil, and I wanted to be part of recording what was going on because they were so enthusiastic."

Though Lips reckons that the whole project has been a bit of a miracle, Robb admits he was indifferent at first. "When I saw the finished movie, I got it. For the few years it was going on, filming us, off-and-on, I was like, 'What kind of movie is this going to be? They're filming everything.'"

As it's whittled down from 320 hours of footage, Robb isn't kidding. As dreams are repeatedly shattered and rebuilt, there are plenty of raw and painful moments on screen, and given how much they've had to struggle, it's tempting to wonder if they wish they could just make a living from their band without having to bare their souls on film as well.

Robb doesn't seem to mind. "Lips wears his heart on his sleeve a lot of the time anyway."

"Oh yeah, I have nothing to fear," confirms his friend. "I don't care if I'm judged; I'm the final judge, so I don't care what anybody really thinks. There's no shame."

Of course, the other way to look at it is that they are finally in the right place at the right time. Gone are the days when bands would be mythologised in Led Zeppelin Hammer of the Gods-style tales of rock'n'roll excess. Now, Ozzy Osbourne is a reality TV star and even the multi-millionaire members of Metallica are prepared to air their problems publicly (as seen in Joe Berlinger's astonishing documentary Some Kind of Monster).

In other words there's an appetite for real stories, something a record company executive in the film inadvertently points out as he tries to find a polite way to tell Robb and Lips that he thinks they're too old: "Your history has value."

Thanks to the film, others are starting to appreciate that. Record companies are waving deals at them, Slayer's manager has decided to represent them, and Coldplay's booking agent is organising their gigs (they'll play the Download festival later this year).

"This has been the best part of the film," reckons Gervasi, "because when the movie ends, the story isn't over. Whenever the band play, that's when the audience gets the chance to see there's a real happy ending."

Anvil! The Story of Anvil is on selected release from today. See our review on page 5