AS rock stars competed to express the depth of their feelings for the plight of Africa on July 2, one musician who seemed genuinely choked to be on stage at Live 8 never mentioned Africa. When, midway through their 20-minute set, Waters announced he felt "incredibly emotional to be back with these three guys again", he meant it. As he tried to sing Wish You Were Here, a song about Syd Barrett, his childhood friend and the band's inspirational founder who left in 1968, his voice cracked and he could barely get the words out.
David Gilmour, Waters's arch-enemy in one of the longest feuds the rock world has witnessed, carried on scowling down at his electric guitar. Although the band played on, none of them had expected such a public declaration from the man who had sued, insulted and mostly just ignored them for 20-odd years. Even Nick Mason, the group's unflappably urbane drummer - and the only member on speaking terms with Waters before the Live 8 reunion - admitted later that "we were all very surprised at the way Roger behaved".
Almost as surprised as they had been in 1986 when Waters launched a legal action to stop his old partners from carrying on as Pink Floyd. Waters had quit the group to launch a solo career in 1985. His view was that as he had written most of the music after their breakthrough album, 1973's Dark Side of the Moon (which sold 35 million copies), without him at the helm, Pink Floyd did not exist.
Mason and more particularly Gilmour - a virtuoso guitarist, singer and songwriter responsible for a handful of Pink Floyd's best-loved tunes, including Comfortably Numb - saw this as breathtaking arrogance on Waters's part, the culmination of years of bullying and megalomania.
A year later, they had fought him and won. What followed were two further Pink Floyd albums, fronted by Gilmour and supported by hugely profitable world tours. And a lot of backbiting. Gilmour's most-quoted comment on Waters was the pithy "Roger is a prick".
Waters, meanwhile, heaped scorn on Gilmour's musical talent and his reliance on others to help with the songwriting, including his wife, the novelist Polly Samson. "So Spinal Tap," Waters bitched. Before they met to rehearse four songs for Live 8, the two men had scarcely spoken for 20 years.
The origins of their feud go back another 30. Most accounts of the beginnings of Pink Floyd start in 1964 at London's Regent Street Polytechnic, where three architecture students, Roger Waters, Nick Mason and Rick Wright, joined forces with a student from Camberwell Art School, Syd (real name Roger) Barrett.
However, the foundations of the band had been laid much earlier in Cambridge, where Barrett, Waters and a young sidekick, Gilmour, had grown up together. Waters and Barrett went to the same primary and grammar schools and were drawn together in part because each had lost his father. Gilmour and Barrett became friendly in their teens and ended up together at Cambridge Technical College. In the summer of 1964 the pair went busking in St Tropez, playing Beatles songs on the streets before getting thrown into jail by French police.
Four years later they were playing together again in far less happy circumstances. Barrett, by then the charismatic leader and songwriting dynamo of the darlings of the British underground scene, Pink Floyd, had taken too much LSD and become an acid casualty. Gilmour had been drafted, initially to hold things together, then, as Barrett's madness took hold, as a full-time replacement.
Peter Jenner, the band's first manager, recalled that Waters "was the one who had the courage to drive Syd out, because it was chaos", but that it hurt. "Syd was the only person, I think, who Roger has ever really liked and looked up to, and he always felt very guilty about the fact that he'd blown out his mate."
According to Gilmour, Waters proceeded to take it out on him.
"I was the new boy. Not only that, I was two years younger than the rest of them, and you know how those playground hierarchies carry over. You never catch up. Roger is not a generous-spirited person. I was constantly dumped on."
Throughout the 1970s, the Floyd's glory years, the two men fought for artistic control of the band. According to Mason, the group's resident diplomat, the arguments usually boiled down to "David's desire to make music, versus Roger's desire to make a show". Gilmour considered himself the superior musician. But it was Waters who had the big ideas that could turn a collection of Pink Floyd tunes into a concept album, such as Dark Side of the Moon or 1975's extended elegy for Barrett, Wish You Were Here.
Spookily, the damaged genius none of them had seen for more than five years suddenly reappeared in Abbey Road studios while they were recording the album about him. Now 100kg and completely bald, Barrett wandered around the mixing console brushing his teeth and offering to help out with guitar solos. That was the last time the original members of Pink Floyd sat in a room together. It was a traumatic meeting for all concerned, and it didn't help to heal the growing rift between two of Barrett's oldest friends.
During the making of the Floyd's next album, Animals, in 1976, Waters and Gilmour engaged in a lengthy wrangle about publishing royalties, arguing over who had written what, which took 10 years to settle. With the next album, The Wall, relations broke down completely as Waters began to treat Pink Floyd as a one-man band: his.
He fired the keyboard player, Wright, and threatened to get rid of Mason, who is the godfather of Waters's son Harry.
"Both Nick and Rick were pretty catatonic in terms of their playing ability after The Wall," Gilmour said later. "They'd been destroyed by Roger."
The indestructible Gilmour, however, found that "to get my point across I had to make increasingly histrionic, stubborn gestures", and he later dismissed The Wall, a thinly veiled account of Waters's childhood, including the death of his father at Anzio in World WarII and his problems in later life as an alienated rock star.
Gilmour's view of the album was that Waters had been "one of the luckiest people in the world, issuing a catalogue of abuse and bile against people who'd never done anything to him". By then he and Waters were doing most of their talking through their lawyers.
And that was the way it looked set to stay. Not even the death last year of the band's manager Steve O'Rourke could reunite Pink Floyd. Waters was not present at the funeral service in Chichester Cathedral when the other three played Wish You Were Here. "Roger still had some differences with Steve," Mason said, "so he wasn't asked."
Whatever prompted this month's dramatic rapprochement, it wasn't any apparent desire on the part of either Waters or Gilmour to re-form Pink Floyd beyond Live 8. Both men have solo albums in the works. This northern autumn Waters is set to release Ca Ira, a musical history of the French Revolution. Next year Gilmour plans to tour in support of the album he has been recording at his home studio in West Sussex. Since the show, Gilmour has turned down a reported offer of $US200 million ($265 million) for Pink Floyd to tour the US, and has announced he will be donating to charity his share of royalties from the huge upsurge in sales of the band's albums since Live 8.
"David was unenthusiastic when Bob Geldof first approached him about Live 8," says Mason. "He sees it as a distraction from his solo work, which it is. He is bound to suffer a backlash from Floyd fans shouting for the old numbers when he plays his new stuff."
So what, if not the famously persuasive Geldof, could have made him change his mind? Only two people know for sure and neither of them is speaking publicly about it. Mason confirms, however, that there was one telephone call from Waters to Gilmour that clinched the deal.
Could this have been the moment when the older man finally climbed off his high horse and addressed his former bandmate as an equal rather than a young upstart? Might he even have apologised? That would certainly explain why Waters seemed so emotional in Hyde Park while singing, or trying to, about Barrett, the man without whom there would have been nothing for him and Gilmour to argue about.
The Sunday Times
Roger Waters, the 60-year-old bass player with Pink Floyd, had reconvened the band's classic formation for the first time in nearly a quarter of a century.