Elvis Presley was my brother

David E Stanley and the King of Rock 'n' Roll. Best mates. Really.

"Elvis, Elvis, Elvis - hey, that's all I've been doing for 17 years. I guess I'm kinda used to it." I guess he is. David E Stanley, 40, ex-bodyguard, ex-drug addict, ex-evangelist, is doing the one thing he has always done best: being Elvis Presley's stepbrother. Having written Elvis, We Love You Tender, and exhausted America's public speaking circuit (the fraternal angle happily guaranteeing full houses), he is now in London promoting his new book. It is, of course, The Elvis Encyclopaedia.

Of the multitude still living off a fat, dead singer, Stanley can at least claim to be well qualified. At the age of four, he was moved into the Graceland mansion, when his mother married Elvis's father, Vernon Presley. "We walked in and there was the King of Rock 'n' Roll and I didn't have any idea who he was," he chuckles.

The following morning, Stanley awoke to find Elvis had bought the entire contents of a toy store for him and his two elder bothers. "Well, my mom saw right off the bat that he would be quite influential. That disturbed her a little bit, to know that this guy was going to have a lot of control over her sons." So much control, in fact, that 36 years later he is still recounting the incident on the other side of the Atlantic.

"When I started school I didn't have any identity - I was just Elvis's stepbrother. Elvis would come to watch me play football, but then nobody watched the game. They were all watching him instead." Home at Graceland was a rock 'n' roll entourage hideout, and his chief playmate was Priscilla. "She was kinda neat."

But with Stanley's adolescence came bell bottoms, long hair, marijuana and domestic tension. "I loved John Lennon. Elvis hated him - he thought he was dangerous. So there was a period where we didn't get along.

"Elvis went to see the President and said, 'Mr Nixon, we have a problem with America. Jane Fonda and John Lennon are corrupting our youth, and my stepbrother is a prime example of that.' He came back and told me he wanted me to be a narcotics agent and nark on all the guys doing drugs at school. Man, can you believe that?" He roars with laughter, and adds without irony: "God bless Elvis. He was very pure."

In 1972 Stanley went on tour with Elvis and saw another side. "Man, it was wild. Private jets, access to anything you wanted. One night he calls me down to the foyer of some hotel, and there are five of the most gorgeous girls you've ever seen. He says to them: 'I give you the boy, now bring me back the man.' I thought, hey, he's cool, man."

First as Elvis's personal aide, then as his bodyguard, Stanley watched him descend from moderate medication levels into massive drug addiction. "I would say, 'Elvis, this is serious shit, this drug thing is for real.' But then I was doing drugs, too, and I thought, hell, Elvis knows what he's doing." But by 1976 it was clear that he didn't. Elvis was bloated, heavily drugged ("Yeah, he was having the odd overdose"), and a book was being written about his drug addiction by former bodyguards. "Elvis got hold of a manuscript and started crying, sobbing that his life was over. I had to watch him piss it all away. I'd keep having to drag him to the bathroom and clean him up. It was very tough for me to see my hero self- destruct like that."

When Elvis died on his bathroom floor at Graceland, in 1977, Stanley was one of the first on the scene. "I'm the only guy who's got the guts to say Elvis killed himself. I knew it right then. He couldn't bear for the world to find out he wasn't the wonderful apple-pie guy the world knew. And that's why I'm here today, why I talk so candidly about Elvis. These days I care about young people, and the problem we have with drugs. I have to tell them what they did to my stepbrother."

Stanley is a very likeable man with a lot of entertaining tales to tell. He is hilarious on Elvis's daughter Lisa Marie and her marriage to Michael Jackson. "Boy, he would have had a fit. Elvis wasn't a prejudiced man, you see," Stanley explains gravely, "but he sure didn't believe in mixed marriages."

But Stanley as selfless anti-drugs crusader is hard to swallow. "At school I made a lot of extra lunch-money selling autographs," he giggles, and that's just what he's still doing today. He has indeed, been "doing Elvis" for 17 years. How does he feel about the rest of the Elvis industry?

"Sick people. There's too much value put on Elvis. All those Elvis earrings and all that stuff, that's wrong. And Priscilla just makes a living off of her name. I don't get it. You know what it is?" He glares. "Vicarious living."