I was still just a little in awe of the Rolling Stones in the mid-sixties. The Beatles were richer and sold more records. But they had compromised their integrity with neat hair and command performances. In London the Stones were the new potentates. Their hairstyles, their attitudes, their clothes were aped by every young man with aspirations to style – from elegant, leisured aristocrats to schoolboys barely out of short trousers. It is hard to remember now just how vast, if transient, an influence they were. No other musicians in history had wielded such power for social revolution.

At the centre of it was Brian Jones. He was the musically gifted Stone, the one who could pick up any instrument – from a saxophone to a sitar – and learn to play it in less than half an hour. The one who was playing pure, soaring rhythm and blues for a living when Mick Jagger was a mediocre student at the London School of Economics and Keith Richard was just another grubby, delinquent art student who thought he was Chuck Berry because he could pluck three chords on his out-of-tune guitar.

Brian epitomized the arrogantly hedonistic attitude that was the mainstay of the Rolling Stones' special appeal. He had left six illegitimate children – all boys and all by different girls – in his wake. He was the one who grew his hair longest. He was the first to wear outrageously androgynous clothes – chiffon blouses and Ascot hats with make-up – and yet carry such an aura of street guerrilla aggressiveness that no one would dare suggest to his face that he looked anything less than totally masculine. Where Brian led the other Stones limped along behind.

Lately things had changed. The word among those who worked with the Stones was that Mick and Keith were inadvertently grinding Brian down, breaking him, destroying him. Egocentric, obsessed with becoming stars themselves, they couldn't forgive Brian Jones for having bent them to his will musically and visually in their early days. Such rumours are common in the tough, bitchy world of rock music, and I hadn't taken them seriously – until now.

I was sipping a scotch on the rocks in a dark London nightclub called the Speakeasy, waiting for my girl friend, a nightclub dancer, to show up. It was two in the morning, and the club was crowded with the young and beautiful men and women who had turned London, momentarily, into the hip capital of the Western world. "Swinging London" may be a dusty cliché now. But then it was a reality we all were working hard to perpetuate.

At clubs like the Speakeasy everyone tries to appear supercool but spends most of the evening looking around for famous faces. You can tell when a star arrives because everyone – even the dancers – starts gaping. When it happened this time, I glanced up, and there, lurching towards me, was Brian Jones.

This wasn't the Brian I knew from twelve months before. Then his golden hair had glowed like the sun, and he had been tanned and lithe and beautiful. Now his hair hung lank and greasy around his deathly pale face, his eyes were bloodshot and the shadows across his face were those of a man who hadn't slept for a long time. "Hi, Tony – how's it going, man?" He smiled, and I ordered him a scotch and felt flattered that the lead guitarist with the Rolling Stones had not only remembered my name but had singled me out among all the other people he knew in a fashionable club like th