The first thing you notice is how close together they are. Led Zeppelin are not scattered around the huge stage of the O2 arena in London like 100m relay runners awaiting the baton, like most bands at this venue. They are huddled within a few feet of each other in the centre of the stage, and they stay that way for most of the two hours or so of Celebration Day, the new movie that captures their one-off return to playing live in December 2007. Jimmy Page might wander off a few feet to hit a guitar pedal, John Paul Jones occasionally sets his bass down to sit at a keyboard, but Robert Plant sings from the heart of the group, just in front of the drum kit – occupied by Jason Bonham, son of Zeppelin's drummer John, who died in 1980. For most of the film, all four of them are in frame simultaneously.

"It was like a shield wall – it was a Romano-British shield wall, and what was coming at us was the idea of failure and ridiculousness – for me," says Plant, speaking on a sunny autumn morning in his local in north London. "It would be precocious of me to walk to the front of the stage and take on a kind of rock singer pose, at that time in my being – and that's five years ago. I could only send it up, and I don't want to do that."

"It was always like that," counters Jones, talking later that day amid the old-money graciousness of the Connaught hotel in Mayfair, where he and Page are both ensconced. "You need to be that close. There's a lot going on, a lot to concentrate on and focus on. Plus, I like to feel the wind from the bass drum."

"This was going to be a critical show," Page says. "We only had one shot at it, so we needed to go out there and do it really well. There was a lot of listening to be done, there was a lot of communication – nods and winks, and you can see this generate through the course of the evening to the point where we're really communicating through the music."

Celebration Day will likely mark the world's last chance to see Led Zeppelin communicating through the music. At a press conference the following day, they will avoid questions about whether they will ever again reunite, but Plant's ambivalence about Zeppelin's role in his current life is evident during our conversation. He talks about how being the singer in the band is "just kind of narrating some bits and pieces which hold together some great instrumentation". He says fronting Led Zeppelin means being specifically a rock'n'roll singer – and how that's not what he is any more; he's a singer. He talks about how the lyrics of those old, old songs are the words of a young man – "There was nothing cerebral about what I was doing at all" – even if he knows his writing got better as the band matured.

And he talks about how the last years of the group were something different anyway, after first he and his wife were seriously injured in a car crash in 1975, and then his five-year-old son Karac died of a respiratory infection in 1977. "My boyhood was over," he says. "I was 27 [in 1975] and flattened. A little premature, but that was it. It was over. Whatever happened after that was going to be different, and so it was."



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What you experience on Celebration Day, then – those extraordinary songs, somehow combining intricacy and technical excellence with the wham! and the bam! of the earliest rock'n'roll – is just a reminder of how things must have been before it had to be different. For almost the whole point of Led Zeppelin is that it was music made by young men supremely confident in their ability to bend anything to their will – hard rock, folk, blues, funk, Arab-influenced epics, balladry. There is no doubt in their music: Dazed and Confused is as inaptly titled a signature song as could be. "There was a Zeppelin swagger, definitely," Jones says drily. "We knew we were good. At our best, we thought we could be a match for any band on the planet. And at our worst, we were better than most of them."

In one way, though, Celebration Day captures Led Zeppelin rather more perfectly than any previous live document: it's tight and punchy and unrelenting. Might it even be a better representation of Zeppelin's strengths than live shows in their heyday, when they might surrender half the set to lengthy solo instrumental excursions? "I think you should ask Jimmy that," Plant says, with a slight laugh. "Time is a funny thing when you're onstage. It did leave me occasionally a little bit adrift. But I'm a Jimmy Page fan, so I like to hear where he goes."

I do put the question to Page, who punches his hand quickly and repeatedly. "Like that!" he says, illustrating the ferocity of their presentation. "That's exactly what we were. That was the intention. We're doing that to bring in the element of surprise."

Then he notices the implicit criticism of lengthy solo instrumental excursions. "Can I just say, the thing with Led Zeppelin in the day – sure, the sets got longer, but it wasn't necessarily because of extended solos. Although that certainly would have helped." The problem, he says, was the desire never to lose anything from the set, even when new songs were added after each album. "We'd start out with a stripped-down show and by the end of the tour we were playing twice as long," Jones says. "And then, the next tour, we'd strip it all down again and start again."

Page formed Led Zeppelin in 1968, after the Yardbirds broke up around him. His first recruit was Jones, whom he had known from the sessions they had worked on in the mid-60s. "I just wanted to stop going crazy and do something creative," Jones says. "And so I thought: 'I don't care what it is, as long as it's good.'" He was followed by Plant and Bonham, a young singer and drummer whom Page travelled up to Birmingham to scout.

Jones remembers their first rehearsal, in a basement in Chinatown, London in August 1968. "You think: 'I hope this drummer's all right, I really do,' because if the drummer's not listening or not on the ball, it's really hard work for a bass player. The first number we played – 'Ah, thank God for that; he's not only good, he's great; this is gonna be a joy.'"

Robert Plant and Jimmy Page onstage in 1975 in the US. Photograph: Neal Preston/Corbis

Page already had a design for the group, having seen the way a new rock scene was developing in the US when he toured with the Yardbirds. "The FM stations were playing full sides of albums. Plus I'd been playing what were called the underground clubs – the Fillmores and places like that – with the Yardbirds. I could see the way it could go. One of the things we didn't adhere to was the singles market. We didn't have to do that because we had the mindset of these stations. It made a difference to how you would sequence the numbers and how one thing would roll into another – the cascading hills and valleys within the music."

The first Zeppelin album came out less than six months after the group had formed, and so began the relentless process of becoming the biggest band in the world. "It was hard touring," Jones recalls. "We toured by car for the first tour. There was another bloke in a little van driving the equipment. We finally got it right and got the private jet. We finally figured it out." It's surprising to see, given Zeppelin's live reputation, that only 295 shows are listed on their website, across the entire course of their career – less surprising that 133 of them were in the US.

The bigger the band got, the more of the world they got to see, and the more their music opened out, assimilating influences way beyond the scope of their hard rock peers. There were visits to India, to Morocco, to other places where 12-bar blues wasn't the muscial lingua franca. "In Morocco, we had some Nakamichi recording gear, which was quite the thing in those days, that Jimmy had got hold of," Plant says. "Every year there was a folklore festival in Marrakech and I got a press pass. I said I was working for the NME. And I could get right to the front with my recorder, and there were a lot of Berber rhythms that were spectacular."

And sometimes, Plant says, they left impressions of their own: "Jimmy and I played in a club in Bombay in 1972. I played drums and he played guitar and it was the only club in Bombay that had a drum kit. Somehow or other we ended up in there with loads and loads of illicit substances. Some guy is writing a book about rock in India – and apparently it was born in this club with Page and me wired out of our faces. I'm not a very good drummer, to say the least, but for some reason or another it left a mark."

When they returned from their travels and the four of them became Led Zeppelin again, the process of integrating the ideas into song began, be it some fragile acoustic snippet, or one of those towering electric edifices – Kashmir, Achilles' Last Stand, In My Time of Dying, Stairway to Heaven – that still startle with their grandeur. It was all done before they reached the studio, hence the fact that even their final album – with Bonham and Page reportedly deep in their narcotic and alcoholic addictions – took only three weeks to record.



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"Page and I were studio musicians originally," Jones says, "and you don't waste time in a studio by trying to figure out the chord sequences. Studios cost money. If you want to work out everything you hire some old house or wherever and just go and sit there for however long it takes. Then you go and record it."The preferred old house was Headley Grange, a former workhouse in Hampshire, where Zeppelin would write and rehearse and then, when ready, summon the Rolling Stones's mobile studio to record the results, with Page overseeing sessions with minute attention to detail.

"I was curious to know how things had been recorded on some of the records that I was really keen on," he says. "From Robert Johnson, where you can hear how he's moving in and out on the mic, to those recordings that were done by Sam Phillips, and the Little Richard records. Where were the mics placed? How many mics were there? I learned various things that I now put into practice. And when I was a studio musician, then I could really see how recording worked, and also how it didn't work – like a drummer who was stuck in a little isolated booth, which was padded out so you couldn't hear any of the natural ambience of his kit. And so I knew instinctively that the drums had to breathe, but the fact was you had John Bonham, who really knew how to tune his drums, he really knew how to make them project."

And so Led Zeppelin developed that huge, spacious signature sound. Plant sounded as if he had hatched from some alien egg, all disembodied yowls and indecipherable screams, compared to the other blues-rock shouters of the day; Jones could arrange songs into new shapes or offer basslines beyond the imagination of other players. And then there was Page's guitar. For all the epic soloing, the Zeppelin records show off a player with a startling lack of vanity: he's always serving the song, and often he's low in the mix, letting Bonham and Jones rumble on before the necessary colour is added. His most effective interjections could be the simplest: the strange, off-key, rhythmic stabs that give the end of Immigrant Song its dramatic tension, for example.

For all that Zeppelin soon became a huge band, they were spurned and mocked by critics. "All you knew was that the Stones got all the press, and we sold a shitload of records," Plant says. Jones remembers being shocked by Rolling Stone's damning review of their first album, and still sounds irritated by the resentment of the group's success. "I thought we were about the most honest band out there," he says. "We were playing music that we loved for the reason that we loved it. I remember reading somewhere a musician saying that at a festival: 'I saw piles of Fender basses.' I thought: you bastard. I had one bass for like eight years in Zeppelin. One Jazz bass, my 1962 Jazz bass – and I know it was 1962 because that was the year I bought it, new."

As with any band, it always comes back to the songs. And when you get as successful as Led Zeppelin did – the record concert attendances, the private planes, the platinum records – your songs cease to be your own: they become owned by the audience, and it is the crowd that grants them their meaning. As Plant says at the following day's press conference about Stairway to Heaven: "Maybe I'm still trying to work out what I was talking about. Every other fucker is."

"Part of the investment for all music lovers is selfish, because it takes us to places we want to be and we want to remember," he says in the pub, more thoughtfully. "It takes us to a different person than the one who's now listening to it."

Page is sanguine about it. He knew what people wanted at the O2, and he was happy to deliver. "There's no way that we could get together, and omit something like Stairway, that would've been insulting to the public. We'd have to do certain things: Whole Lotta Love's obviously gonna be in there, Kashmir just has to be in there, and Stairway."

But, Plant points out, the music still holds its power because it has not been overused: it doesn't represent anything but itself. "Because we haven't gone out and flogged it, there's an anticipation and a memory of it being clean and pure and not part of some sort of threshing middle-aged circus, which I think is very much to our credit. If we'd been part of the merry-go-round year after year, or every two years, I think it might have damaged everything."

A degree-course's worth of books has been written about Zeppelin over the years, all containing their share of astonishing and horrifying stories. If only a fraction held any truth – and there are simply too many tales of violence, paranoia, underage groupies and the like for some of them not to be true – you can still be fairly certain that being in Led Zeppelin in the 1970s made possible decadence beyond imagining, and misbehaviour beyond mere condemnation. The tales provide ample fodder for those who see the band as vile representatives of a predatory, aggressive, arrogant male sexuality, even if for others they feed into the image of Zeppelin as the fullest representation of rock at its most swaggering. Ask them about what is often referred to as their "aura", though, and you meet a brick wall.

"It's the music," Page says. "My life has been about that, not just trying to create a stir over something else that's irrelevant to the music. I'll tell you something: in all those books you won't get any more understanding about the music than you will by actually listening to it. It's not about some bit of insanity over here, it's about that music that's recorded across those albums."



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"Any peripheral bullshit left me cold and still does," Plant says. "The band was always four guys that got together and played and when they get together it becomes a different chemical combination. And in the middle of all that, there was probably a tiny fraction, a minuscule amount of what might be there now, of people being 'busy', people who were angling, people who wanted to encourage and advance their interests. It was a good thing to be near, because it was so powerful when it worked. It was an amulet for a lot of people."

Perhaps they are ashamed of what went on. Perhaps they feel not acknowledging the legend contributes to their lasting impact. Because, in a way, Zeppelin knew it wasn't really only about the music. Hence the attention lavished on their album sleeves. Led Zeppelin III – the one with the spinning card; Led Zeppelin IV – the one with no writing on it and the four symbols inside; Houses of the Holy – the one with the creepy cover of naked kids on the Giant's Causeway; Physical Graffiti – the one with the die-cut sleeve so the inner bag became part of the design; Presence – the one with the strange black obelisk and the embossed band name; In Through the Out Door – the one in the brown paper bag. Their albums were events.

"It was a major part," Page says of the designs. "It was quite interesting with the fourth album. We were getting flak from the press because they really couldn't understand what we were about. OK, we'll show you what it is, we'll put out an album with nothing on it, because it's what's inside that's going to be the important thing."

Of the three remaining men who once conquered the arenas of the world, you would bet on it being Page who most wishes they could do it again, though guessing what he's thinking is almost certainly a mug's game. After the band broke up, Plant was able to forge a successful solo career; after a period in which he "couldn't get arrested", Jones became an in-demand producer. Only Page never quite seemed to find a new musical home. Curiously, with his long white hair, he's the one who still looks most like a rock star from the days when bands were still big. And to hear him talk, you wish you could have been there during those days, too. "Sometimes we'd really be going at such a speed, to see whether we could really do it," he says of the band's shows back then. "If you go out with that sort of attitude, you're not going out there to fool around. There might be an area where it might dip – but it certainly comes back with a fury."

"All these cliches and terms that are used for whatever we were are fine," Plant says. "We were just a bunch of guys who could play in many different ways. And for young guys who were loaded with expectations of life and its promises, sometimes a tough backbeat doesn't hurt."