On the last Saturday of June, close to midsummer, Reykjavik isn’t doing night-time. It’s 24-hour daylight. Ask a local if it gets any darker than this and they laugh at you, sometimes while ingesting snuff. There was an Icelandic film once called Insomnia where a cop investigating a murder went psychologically weird because of the no-night-time thing; it was then remade with Al Pacino and set in Alaska. Increasingly, as the hours pass, this is how you feel in Reykjavik; on the very brink of losing it, but in a pleasant, light-headed way. Iceland is bigger than the British Isles, with only around 300,000 inhabitants.

The lupin-dotted landscape between airport and city is lunar, though not as lunar as it was a decade or so ago. Already, more little Lego houses are sprouting up. Even here. Changes to the Icelandic landscape are a hot topic here, and are the reason somebody - I’m still not exactly sure who, such is the vagueness at the core of the Icelandic mentality - has flown me here, let me run around for about 25 hours, then sent me away again at four in the morning. Which isn’t like a normal four in the morning, if you’ve been following so far.

Within the allotted time span, time being a nebulous concept, there is a massive open-air concert in Laugardalur Park, where local heroes Bjork and Sigur Ros play to over 15,000 people, many of whom have brought their children and/or dogs. You’d spend half your time trying not to trip over stuff even if you weren’t spaced out. This is in the evening, really, even though it is sunny and everyone is eating sweets. The event, probably the biggest ever gig in Iceland, is to draw attention to certain environmental issues. Bjork and Sigur Ros are displeased about the impact of growing aluminium smelting activity on the country’s strange and natural beauty. Bjork originally wanted this show to take place on a remote island that could only be reached by ferry once a day. She has said, “Too often battles being fought for nature turn into something negative and into mudslinging. We will not go that way, we are not saying that this and that is forbidden, we are rather asking about other possibilities. The 21st century is not going to be another oil century but rather a century where we need to recycle, think green and design both power plants and our surroundings in harmony with nature.”

That’s the grown-up stuff. Talking to me at the aftershow - EXCLUSIVELY!! - because I have yelled “Hey! Bjork!” and grabbed her by the arm - she adds, “Listen to this mash-up, it’s brilliant, it’s my favourite, it’s ‘Smack My Bitch Up’ by The Prodigy with ‘Orinoco Flow’ by Enya. Isn’t it great?” Then she says she’s been writing letters to Icelandic politicians for eight hours a day for weeks. I don’t quite grasp the nuances of what she’s saying because now she’s introducing me to her yoga instructor, who stretches her leg far behind her back and says, “Can you do this?” The funny thing is, I can, having been taught to do it as a means of recovery from a football injury a couple of years back.

"My voice was shit", Bjork says. "I sounded like Johnny Cash."

Eventually it dawns on Bjork’s yoga instructor and myself that we are doing competitive leg stretches on the edge of the dance floor at an aftershow party, and, even in Iceland, this may be perceived as odd, though not very. Bjork rejoins us. Her chosen DJ is playing T. Rex and MGMT. Everyone pauses to sing Happy Birthday in Icelandic to one of the string section, as they have already done, with 15,000 backing vocalists, during the gig. I tell her it was a great show, as you do. “My voice was shit”, Bjork says. “I am so frustrated. I finally get to play a really big hometown show after all my life. And I lose my voice the week before. I sounded like Johnny Cash out there.” She does a demonstration. Bjork is doing her Johnny Cash impression, right now. “That’s not necessarily a bad thing”, I offer. “Or Rod Stewart”, adds one of her friends/fans/hangers-on, “you sounded like Rod Stewart.” Bjork’s working a face-paint-and-multicoloured-garb combo that’s a bit Native American Pocahontas, a bit Apocalypse Now, a bit Jackson Pollock. The highlights of tonight’s show, which flung in lots of bells and whistles and drums and stamping, were ‘Bachelorette’ and ‘Hyperballad’, but then I like the ones with swoony tunes more than the heavy techno crunchers; call me old-fashioned.

I’m just relieved she remembers me. Many moons ago I did the first interviews with The Sugarcubes. I made ‘Birthday’ single of the week in a prominent music paper and the whole of Iceland thought this meant it was number one in the UK (true). Bjork and co were then art-punk rebels and smartly did nothing to disabuse their compatriots of this notion. The first time I met her I was waiting for her with her bandmate Einar - who is now teetotal and the organiser of this huge concert - and she skipped into someone’s living room flapping her wet hands about. “Hi!” she giggled. “Sorry I’m late. I was just shitting.” Then I went to Paris with them, where we laughed at sex shops, and America, where I watched them with Kim Deal, who told me they made her want to piss like a racehorse and dance like a black woman. “I want to eat life”, Bjork told me. “If I could do this, I would do it. I would like to die by being eaten by a tiger or being hit by lava from a volcano.”

As a young man, like most young men, I was at the centre of things. Naturally we spent time in Iceland back then, too, when lethal Brenivin was drunk and we swam in the blue lagoon, a heated spring in the middle of a lava field. It is disorientating to come back now, after a lengthy absence. It is still dazzlingly clean. Much has shifted. Bjork is an international star of music and film. It’s not exactly awkward talking to her, now, but it’s not like she asks me how I’ve been. Sigur Ros are favourites of The Culture Show and of Radiohead, revered here, and a UK top five album act (as of last week). Nobody seems to drink very much, except Sigur Ros. If you say a band is from Reykjavik, people do not laugh, and patronise them as lovable aliens, like they did then. I am no longer at the centre of things. This is the “psycho-geographical” element of the piece.

Iceland may be fucked. It is in heavy debt, I am told, which is one reason they want to increase their industrial output. But that would spoil their USP - the nature, the goblins and trolls, the belief in the occult, the waters, the geysers, the puffins. As part of our press trip we are to be taken to a waterfall in South West Iceland where hydropower stations are to be built. This will destroy part of a gorgeous river. We will be shown an ancient sheep pen and the earthquake fissures from the largest lava flow since the end of the last Ice Age. We will meet a local farmer. We imagine him waiting there for us, in the middle of nowhere, all dressed up in his best waistcoat and trousers and excited to see human beings, perhaps even masturbating furiously when the first female gets off the minibus.

Except, this being Iceland, the minibus forgets to collect the nice lady from The Sun and I from our hotel (which is an exquisite balance of style and comfort). We wait for a bit. No, they’ve gone, from the other hotel. There’s been, not for the first time, a communication glitch. So we bunk off Green School lectures and visit the blue, blue harbour, where the wind is bracing. We go up the viewing tower of the Hallgrimskirkja church and hear the mighty bells, and, on impulse, because we’re near it, explore the Einar Jonsson Museum. Jonsson (1874-1954) was Iceland’s first sculptor. He totally rocked. One of his sculptures depicts a man sucking off a cow.

I take a photo. There’s another one called “Slut”. Turns out that’s Icelandic for “The End”. Ha ha, we go. It says “Slut”. Then we go to eat and drink. I am no food expert as it tends to get in the way of my fags but the food in Reykjavik is invariably fantastic. Drink’s pretty good anywhere. We wonder whether we’re being good travel writers or rubbish travel writers. We did see the sculpture of a man sucking off a cow. That was a coup. You don’t get much of that in Margate. We decide we probably need to see one more interesting and unusual thing before the gig. We go into an art shop called DEAD. It’s pitch black inside. “This is it“, I muse. “Provocative art statement. We‘ve found another good one.” “Sorry”, says the proprietor, “we have a power failure”. I buy a t-shirt with a picture of a man’s face on it. It is cheap (unlike most things in Reykjavik) and I need more layers as it’s going to be freezing tonight. “Who is the man with the face?” we ask. “It is Iceland’s greatest poet”, is the reply. He says a name of about nineteen syllables; I don’t retain it. “Are you going to the concert?” he asks. “Yes, you?” “Of course”, he says, “everyone is going. Everyone.” He’s right. The streets are deserted. It’s brilliant. It’s like we’re in Magic Town. The last thing we want to do is go to a rock concert with the herd, but, you know. “Why is your shop called DEAD?” “Why not?”

Sigur Ros have taken to dressing up, and, at least at the aftershow, smacking people’s bottoms.

Back at the politics, Sigur Ros vocalist Jon Thor Birgisson says this: “We are not a political band and don’t think musicians should set themselves as spokespeople on anything at all, but sometimes you see things going on in your own back yard and find that just as a human being you cannot stand by and do nothing.” On stage, their drummer is wearing a magnificent crown. Sigur Ros have taken to dressing up, and, at least at the aftershow, smacking people’s bottoms.

In local paper The Reykjavik Grapevine, Bjork has written a lengthy article. It begins, “An Icelandic senator has called me childish because I want to protect nature, which I find peculiar….when the whole world is holding its breath because global warming might kill all the humans within 50 to 100 years, I find it incredibly childish to increase our CO2 emission by 19 tons per capita, placing us in third place worldwide, just after Australia and the U.S.” This despite the fact that the Icelandic prime minister “was recently rewarded by Newsweek as the greenest in the world”. Bjork goes on logically, “Unfortunately, we cannot be green and non-green at the same time”.

We’re at the concert again now. Struggling to see. We find, ten minutes’ walk through a sort of forest, the only place in the vicinity selling alcohol. It’s a café in a garden centre. It sells ice cream too. Wafting across the grounds we can hear Bjork singing, and yelling, and giving it her all in a show that means a hell of a lot to her and her impeccably well behaved crowd. She doesn’t sound like Johnny Cash at all. A burly Icelander - they’re all burly, except for Bjork - stumbles over. “English”, he says, “Can I give you a hug?” I hesitate, because I am cold in many ways, and also Welsh, then say, “Oh, go on then.”

Well, I guess this is Slut. Three hours later we have to be up to go back to the airport. There, delirious with sleep deprivation on top of the displacement the bright and beautiful Reykjavik customarily provides, the now reassembled press corps dump our last Icelandic money on caviar, hats and vodka. “Did you see those sculptures on the road just now?” someone says. “I thought they were men, at first. But they were made of rock.”