Slipknot UK tour: The band is riding high in the charts - but who exactly are their fans?

The chart-topping nu metal band are touring the UK, scary masks and all. But can a newcomer appreciate their music? Simmy Richman heads for the mosh pit to try to discover their appeal

Metal heads: the group wear a series of masks inspired by singer Corey Taylor’s love of horror films

If your taste in music veers more towards old vinyl than nu metal, it's hard not to take the name of Slipknot's latest tour to heart: "Prepare for Hell". Still, it's good to get outside your comfort zone, so here I am at the Manchester Arena to catch the band on the fourth date of their first UK tour for six years. The band is halfway through the world tour, which showcases their .5: The Gray Chapter album, their second to top the Billboard charts in the US.

Over their two decades together, singer Corey Taylor has become fond of referring to the band as his "crazy dream". But if Slipknot is what he sees when he turns in for the night, you wouldn't necessarily want to be sharing a room with him. The group, for the uninitiated, is made up of nine members who wear a series of masks – inspired by Taylor's love of horror films – which are said to reflect their various on-stage personas. In the early days, the masks also served to hide the band's identities, though this changed in 2010 when the group appeared unmasked at a press conference following the death of the group's original bassist, Paul Gray. Since then, the masks have been more about performance than protection (though it must be said that percussionist Chris Fehn would probably get more hassle on his frequent rounds of golf were he to appear on the stages of the world's mega-stadiums unmasked).

Gruesome, terrifying and grotesque, Slipknot's shows are a celebration of the dark side that, you would be forgiven for thinking, will be populated entirely by men reluctantly prised away from violent video games.

It is surprising, then, to see the sheer range of metal fans Manchester has to offer. For a start, there are more women here than I expected. There are also a great many young people who, aside from a preference for black band T-shirts and blacker eye make-up, would look just as at home at a Justin Bieber concert. Before the show, I stop a group of kids, no more than 14, and ask them why they are here and what I might expect. "They're just a great band," one of them tells me. "With awesome drumming." "Their music is more meaningful," one girl wants me to know, "than Nicki Minaj." Do their parents know they are here? "Yes." What do they think of this music? "They hate it."

Clearly, that's not always the case. One boy, who looks about seven, is here with his dad. Fathers and sons, mothers and daughters, frolicking couples. Manchester United keeper David de Gea later tweets a picture from the concert. Slipknot's appeal is wide and strangely heartening. There might be more to this phenomenon than meets the eye.

I take my seat and prepare to enter into the spirit of the 'Knot, a band that are as far from my musical comfort zone as it is possible to find. They come onstage – I know this only because I look it up later – to a song called "Sarcastrophe". The lyrics go like this: "Wallow in the winter of it/ Discover what you truly covet/ Underneath and far above it/ You slither in all kinds of shit… Burn up in your atmosphere/ Burn up in your utmost fear." The titles of other Slipknot favourites played tonight give you a further idea of the subject matter on offer. "The Heretic Anthem", "The Devil in I", "Psychosocial", "The Negative One" and "People = Shit".

Slipknot fans at Download Festival in 2005 (Getty) (Getty Images)

The show itself is a brutal assault on the senses and insanely over the top. As well as the standard bass, guitar, drums, there is a "keyboardist/sampler" called Craig Jones, who, if his onstage Hellraiser mask is a reflection of his inner self, must be a very spiky personality indeed. On either side of the stage are hydraulic platforms upon which two percussionists play what is described as customised drums. These are essentially two large bass drums turned on their side, two floor toms and two empty beer kegs, which get pounded until the organs inside my body shake. It is a relentless performance, and though I must confess that I don't quite make it to the end of the show, it's safe to assume that I don't miss an acoustic section or a greatest hits medley.

Throughout, the only people working harder than the band are the security guys at the front of the stage whose job it is to collect the endless stream of people being passed forward above the heads of the mosh pit.

There are some 20,000 people here tonight and, it seems, each one of them knows by heart every indecipherable word, even if Taylor's vocals sound more like a growling hyena in pain than they do a vocal performance. Though their music is variously labelled death metal, nu metal or alternative metal, the band prefer the term "metal metal" and, when a tune is discernible, there are further influences from the funk-rock of the Red Hot Chili Peppers and the brasher side of the Beastie Boys. Assuming, that is, you were listening to them through burst speakers.

Which probably makes the live Slipknot experience sound more painful than it was. There is, aside from the theatricality and occasional glimpse of musicality, more to Slipknot than meets the eye, a fact verified by their recent nomination for a Grammy, which, were they to win, would, according to Taylor, "scare the shit out of those straights". Taylor also tells us that his band is "bringing real soul and real heart back to heavy metal music". Which may well be true.

So what exactly is the key of Slipknot's enduring appeal? All I can guess is that the unrelenting nihilism, Spinal Tap Satanism and general life-is-shitness of their music reflects the fact that the world is a messed up place and so we might as well have music that celebrates and acknowledges that reality. "In the dark times, will there also be singing?" Bertolt Brecht asked all those years ago. "Yes," he concluded, "there will also be singing about the dark times."

Further to that, it struck me, that being surrounded by people who don't look like me or dress like me and who all share a love of something that I cannot begin to understand, is a deeply alienating experience. Perhaps that's what the "straight" world feels like 99 per cent of the time for the people who go to Slipknot concerts. And if that's the case, who would want to deny them their moment of communion?

Slipknot's Prepare for Hell tour continues. See slipknot1.com for details