In a bashed-up blue transit van in a parking lot in Kansas City, Ted Owen, an auctioneer from Bonhams, London, was given a glimpse of $300,000 worth of Elvis Presley's possessions: guns, a stage suit, diamond jewellery. He then knew he had finally penetrated the "Memphis Mafia", the coterie of Elvis's former bodyguards, school and army chums, upon whom the King showered expensive gifts.

Mr Owen, a diminutive Englishman, beat rivals from the big New York auctioneers, Christie's and Sotheby's, in persuading the mafia that it was time to sell the half-forgotten contents of their garages and bank vaults. Elvis, after all, would have been 60 this year.

Next Friday and Saturday's 2,213-lot auction of Elvis memorabilia at the Hard Rock Hotel and Casino, Las Vegas - which Mr Owen has put together in collaboration with the American auctioneers Butterfield & Butterfield - is the biggest, probably the ultimate, Elvis sale. Its expected total of $3m will be boosted by the sale of an unreleased Elvis recording, "Let Me Make Believe", from the collection of his former chief bodyguard, that could fetch $150,000.

The owner of the bashed-up blue transit van was Elvis's "unofficial official" photographer, Sean Shaver - six feet six inches tall, big belly, cream Stetson with plume of feathers, jeans, checked jacket and shirt. He did not take to Mr Owen straight away. Entering his hotel room at 6pm, six hours late for their assignation, he rasped: "You smoke, I'm outa here".

"I'll open the windows," said the mild-mannered Mr Owen: "Please, I've come a long way". For months, his phone calls from London to members of the Memphis Mafia had gone unanswered.

"Naw, I'm hungry. I wanna have breakfast," said Shaver and turned to go.

Breakfast at six in the evening? Mr Owen was beginning to find out about the Memphis Mafia lifestyle. Being with Elvis meant turning night into day and, 18 years after his death, some have still not reset their body clocks.

Finding himself, by some fluke, in the passenger seat of the bashed-up blue van, Mr Owen faced another tribulation. Non-drinkin', non-smokin' Shaver chews raw garlic. The dashboard ashtray was full of cloves.

"Does it smell in here?" asked Shaver, pointedly.

"No, Sean, it's fine".

Shaver gestured towards the back of the van. "I suppose you wanna have a look at some of this ol' shit I got in here."

At first, all Mr Owen could see was a couple of unwholesome-looking pails filled with nappies. Like all Memphis Mafia, Shaver remains strongly security-conscious. "No one ain't gonna rob a car full of diapers."

The fortune in Elvis memorabilia was lifted out of its cardboard boxes. Then: "Somebody might be watching". Shaver revved the van's oversized, perfectly-tuned engine and sped around town, sometimes doubling back on his tracks, before parking, locking up and walking to a diner 200 yards away.

Over a "breakfast" of pasta and salad with thousand-island dressing, washed down with Coke, Shaver mellowed. "You're quite a nice little guy", he told Mr Owen, "I can see you ain't out to fuck us up."

The burly teetotaller later made a magnanimous gesture, taking him to a bar and buying him beer. "At first I'd been really intimidated," Mr Owen recalls, "but it was just a ritual checking-out. He turned out to be every bit a gentleman."

Shaver has moved house three times to escape Elvis fans over-interested in his collection of 100,000 unpublished photographs of Elvis, dating from the early Sixties, on and off stage. The 30 colour negatives of his in the sale, estimated $100-$200 each, are just a sample.

Mr Owen's chance to mix with the mafia came because he did a favour for Elvis's friend, Charlie Hodge, an army buddy and musician who was his "fall guy" on stage, handing Elvis scarves to dangle before his screaming fans. Hodge had brought to England Elvis's boxed pair of Colt pistols, as props for a lecture, and had had to abandon them here because of firearms export regulations. Mr Owen succeeded in retrieving them. It was Hodge who pushed the idea of a big sale.

As word spread about the "nice little guy from England", Mr Owen was telephoned from Los Angeles by Dick Grob, former police sergeant and Elvis's chief bodyguard. "Grob the Fox", as Elvis dubbed him, said: "I don't know if it's Elvis. I want you to come and hear it." It turned out to be the unreleased and un-aired acetate recording, "Let Me Make Believe".

Then came an invitation to the Phoenix, Arizona, ranchhouse of Paul Lichter, author of 12 books on Elvis, who produced another rare acetate and three jumpsuits among 200 items of memorabilia. Two of the jumpsuits, including the dark red one worn by Elvis on the cover of his last chart-topping single, "Burning Love", are each estimated $100,000-$120,000.

Grob has also consigned a score of the guns he helped Elvis collect during his seven years as head of security at Graceland, Elvis's Memphis home. Elvis was trigger-happy, as the bullet holes at Graceland testify. He used to shoot up TV sets if the performers on screen displeased him. None of his sub-machine guns are in the sale, but his .38 Colt revolver with gold TCB logos is, estimated $10,000-$15,000.

That TCB, with lightning flash, stood for "Taking Care of Business". Elvis gave his closest aides gold TCB pendant necklaces, said to be an irresistible lure for women. A diamond-encrusted TCB necklace is estimated at $60,000-$70,000. Looks like the ageing Memphis Mafia are putting business before pleasure these days.

If you would like the Elvis Presley Memorabilia catalogue to the sale (pounds 20), or to find out how to bid, phone Bonhams on 0171-393 3900

Ten of the best (affordable) Elvis mementos in the Las Vegas auction:

1 Invoice for Elvis's muskrat coat..... ...... $200

2 White velour turtleneck worn by Elvis .$500

3 Signed photo of Elvis in Stetson $400

4 Macrame plant holder from Graceland $200

5 Unused bottle of Teddy Bear perfume $100

6 Elvis's SS officer's dress knife (rusty) $200

7 "Blue Hawaii" cast party mug $300

8 Piece of carpet from"Lisa Marie" jet.. $300

9 Priscilla Presley's safari-style shirt $200

10 Elvis's hair trimmers (rusty) $700

Prices are based on auctioneers' lowest estimates. There are approximately 1.5 US dollars to the pound