As gigs go, an abandoned gas turbine research complex at 4am has to be one of the more bizarre settings. But that is where a ragtag band of friends and hangers-on are heading. The band are Blacksand – Charlie Casey and Nick Franglen – and they have decided the huge, spooky setting is ideal for their series of “one-off performances in unusual locations”.

In a previous outing the band ventured into the ancient Box Freestone Mine in Somerset. During the three-hour hike one person broke a rib and two people were bitten by leeches. Their next “gig” is on a damaged submarine in the Thames. Franglen is a keen diver and instead of paying the owner for the use of his vessel, he will do a dive to locate a suspected leak. One hopes it’s a pay-in-advance deal.

Blacksand take “extreme gigging” very seriously and they are not the only band at it. Everywhere from chip shops (Badly Drawn Boy) to forests (Pulp and lots of others, thanks to the forward-thinking Forestry Commission) to London’s black cabs have become ad hoc venues.

Public libraries have even cottoned on to the appeal of live music and launched a Get It Loud in Libraries campaign. They shed their fusty image; bands get a quirky story.

And “quirky” is significant, as even though there seem to be more bands than ever and music is everywhere as a backdrop, there are in fact fewer proper ways to reach a large audience and to distinguish yourself. Of the small number of primetime TV music shows, only Later. . . and The Friday Night Project have any clout and the same major label “buzz” artists scrap for the exposure. Equally, radio is a closed shop unless you have the weight of the industry behind you. Everyone else is left to create their own attention-grabbing platforms, which they are doing with gusto, empowered by cheap recording equipment and the internet.

Pioneers in the field are the Black Cab Sessions, gigs performed in the back of a London taxi and filmed for a website of the same name. The brainchild of a film production company, band manager and music mad City worker, they were devised as a way to promote their club night, as they couldn’t afford advertising. The online show has become a global hit.

Hailing a cab in London can be tricky at the best of times, but try doing so with a group of people armed with a boom, a video camera, a guitar, banjo and violin. It won’t work, which is why the lead singer of the band Fireworks Night acted as bait and sweet-talked the driver into letting us all in.

Amid a tangle of legs, guitar and banjo necks and violin bows, the band’s first attempt at playing was stopped abrubtly when we hit a speed bump exactly as the violinist Genevieve began her solo. The second attempt was perfect; holding her bow in the middle gave Genevieve the control she needed, even as we flew round the IMAX roundabout at Waterloo, twice.

Outside, no one seemed to take any notice. Even the cabbie, Brad, maintained an “I’ve seen everything” face. But his nonchalance fell away when at the end he was asked to introduce the band to the camera.

“The drivers love it,” explained Chris Pattison, the Sessions’ co-ordinator. “The best was last week. We recorded one with New Yorker Baby Dee. A flame-haired transvestite, she’s not everyone’s cup of tea but the driver loved it so much he bought a ticket for her concert that night.”

The band looked dazed but exhilarated once it was all over. “It’s good to test yourself,” noted singer James.

Speedbumps are one thing, yomping for an hour through a pine forest by moonlight is another challenge entirely. Especially with a kit that includes a power supply on wheels (a modified marine battery), two electric guitars, a mixing desk, laptop and endless bags of wires, distortion boxes and effects pedals.

This is what Blacksand have brought along for their turbine spectacular. The band say that their music and concerts are antithetical to the “have it now” culture of instant downloading. “It would take a year to download one of our tracks,” laughs Casey.

Franglen says: “My ideal performance location is somewhere that takes a long time to get to, involving at least two different forms of transport and then quite a long walk to an empty building you have never been in before. At night.”

So this is why our small group is waiting in a petrol station car park at 2am. We have been instructed to give one flash of the car headlamps, followed by the phrase “The lighthouse is much colder in wintertime. ” We were also told, “You will get muddy, possibly all over.”

After a few false starts flashing the wrong cars, we locate each other. We are a ten-strong team. We march off into a pitch-black forest, arriving at a clearing at about 3am. Franglen goes ahead armed with his wife’s grandmother’s spade to inspect the site’s security fence. His disappearing silhouette looks like something out of an Alan Moore graphic novel. Within seconds he has been swallowed up by mist.

Hours seem to pass; we panic that Franglen has been caught. In fact, because we were all told to turn off our phones, he couldn’t contact us. This is the kind of elementary mistake you get with a bunch of music enthusiasts rather than professional ramblers. Once united, we squeeze through a muddy gap that handily was already there. Popular place. We scoot past a burnt-out van and then slide, on our backs, under another fence. Once we are through, there’s a slalom of pipes to duck under, metal ladders to climb up, platforms to scamper along. The whole thing feels like a cross between Doctor Who and Buster Keaton.

Amid a vast complex of buildings, our destination is a turbine hall where Britain’s greatest technical minds once made history testing engines. In 1970 the electricity bill for the plant was reportedly £6,000 an hour. Air was blasted down pipes at three times the speed of sound. “Imagine the noises this place must have made,” whispers Franglen. Blacksand make instrumental electronica. Franglen, who is classically trained, was formerly in the million--selling Lemon Jelly and has produced John Cale. Casey is an indemand session guitarist. Their new project is all improvised, their pieces informed by their surroundings – the stranger the better.

Once inside, it takes the pair more than an hour to set up by a huge airlock on a platform at least 50ft above ground. They might appear to be indulging in hairbrained schemes, but are also, perhaps inconveniently, perfectionists. They mike up the whole space, taping microphones high in the roof and deep inside huge funnels. The idea is not just to record themselves, but the music mingling with the creaks of the building, the coos of the pigeons and, hopefully, some blackbirds.

It’s 6.59am and the pair are finally plugged in; an array of effects pedals with names such as Nightmare and Cheese Source lie at their feet. They are the only colourful objects in a vast space filled with every variant of grey and dust colour imaginable. Looped notes create a lullaby-like soundbed; the pair then distort notes over the top. The whole room feels like a sleeping giant awakened.

But by 7.12am it’s all over. A guard has apparently been spied and for Casey, a gentle soul whose wife is pregnant and who has to fly to Canada the next day, a morning in custody is not an option. While anticlimactic, this outcome seemed somehow perfect for such a ludicrous venture. Escaping in daylight results in even more comedy capering, with people trying to appear invisible while lugging bags of kit through the rain. Amazingly, we bump not into guards but two other “urban adventurers”. After the shock, there is a wink and everyone passes on.

“It was quite something, wasn’t it?” says Franglen later over a breakfast pint. “A shame there wasn’t more music, but it’s unlikely enough that there would be any at all, so that makes it a triumph in my book.”

As gigs go, Blacksand certainly like things more off-piste than most. But with even super-star artists such as R.E.M. performing in the back of a Volvo estate for the French film-maker Vincent Moon (who is credited with kickstarting the phenomenon with his Concerts à Emporter), the message is clear – the whole world is a stage, and musicians (mostly those who own laptops and cheap, transportable recording equipment), imaginative players looking to be excited and be exciting upon it.

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